diff --git a/Userland/Libraries/LibGUI/AboutDialog.h b/Userland/Libraries/LibGUI/AboutDialog.h
index 92c2f4b2335..93290749b14 100644
--- a/Userland/Libraries/LibGUI/AboutDialog.h
+++ b/Userland/Libraries/LibGUI/AboutDialog.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -31,7 +31,7 @@ private:
     AboutDialog(StringView name, StringView version, Gfx::Bitmap const* icon = nullptr, Window* parent_window = nullptr);
 
     DeprecatedString m_name;
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     DeprecatedString m_version_string;
 };
 }
diff --git a/Userland/Libraries/LibGUI/AbstractThemePreview.cpp b/Userland/Libraries/LibGUI/AbstractThemePreview.cpp
index e3c65230483..11a2f427085 100644
--- a/Userland/Libraries/LibGUI/AbstractThemePreview.cpp
+++ b/Userland/Libraries/LibGUI/AbstractThemePreview.cpp
@@ -67,7 +67,7 @@ void AbstractThemePreview::load_theme_bitmaps()
     load_bitmap(m_preview_palette.tooltip_shadow_path(), m_last_tooltip_shadow_path, m_tooltip_shadow);
 }
 
-void AbstractThemePreview::set_preview_palette(Gfx::Palette const& palette)
+void AbstractThemePreview::set_preview_palette(Gfx::Palette& palette)
 {
     m_preview_palette = palette;
     palette_changed();
diff --git a/Userland/Libraries/LibGUI/AbstractThemePreview.h b/Userland/Libraries/LibGUI/AbstractThemePreview.h
index 203c4084064..a73300b2383 100644
--- a/Userland/Libraries/LibGUI/AbstractThemePreview.h
+++ b/Userland/Libraries/LibGUI/AbstractThemePreview.h
@@ -22,8 +22,8 @@ class AbstractThemePreview : public GUI::Frame {
 public:
     virtual ~AbstractThemePreview() override = default;
 
-    Gfx::Palette const& preview_palette() const { return m_preview_palette; }
-    void set_preview_palette(Gfx::Palette const&);
+    Gfx::Palette& preview_palette() { return m_preview_palette; }
+    void set_preview_palette(Gfx::Palette&);
     ErrorOr<void> set_theme_from_file(StringView path, NonnullOwnPtr<Core::File>);
     void set_theme(Core::AnonymousBuffer const&);
 
diff --git a/Userland/Libraries/LibGUI/AbstractView.cpp b/Userland/Libraries/LibGUI/AbstractView.cpp
index ddb67526258..26aa2320e39 100644
--- a/Userland/Libraries/LibGUI/AbstractView.cpp
+++ b/Userland/Libraries/LibGUI/AbstractView.cpp
@@ -221,7 +221,7 @@ void AbstractView::notify_selection_changed(Badge<ModelSelection>)
         update();
 }
 
-NonnullRefPtr<Gfx::Font> AbstractView::font_for_index(ModelIndex const& index) const
+NonnullRefPtr<Gfx::Font const> AbstractView::font_for_index(ModelIndex const& index) const
 {
     if (!model())
         return font();
diff --git a/Userland/Libraries/LibGUI/AbstractView.h b/Userland/Libraries/LibGUI/AbstractView.h
index 38860be327d..1ff695f3f02 100644
--- a/Userland/Libraries/LibGUI/AbstractView.h
+++ b/Userland/Libraries/LibGUI/AbstractView.h
@@ -109,7 +109,7 @@ public:
 
     void notify_selection_changed(Badge<ModelSelection>);
 
-    NonnullRefPtr<Gfx::Font> font_for_index(ModelIndex const&) const;
+    NonnullRefPtr<Gfx::Font const> font_for_index(ModelIndex const&) const;
 
     void set_key_column_and_sort_order(int column, SortOrder);
 
diff --git a/Userland/Libraries/LibGUI/AbstractZoomPanWidget.h b/Userland/Libraries/LibGUI/AbstractZoomPanWidget.h
index 4de8f29a339..3c079ddf81d 100644
--- a/Userland/Libraries/LibGUI/AbstractZoomPanWidget.h
+++ b/Userland/Libraries/LibGUI/AbstractZoomPanWidget.h
@@ -78,7 +78,7 @@ private:
     float m_max_scale { 10.0f };
     float m_scale { 1.0f };
 
-    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> m_saved_cursor { Gfx::StandardCursor::None };
+    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> m_saved_cursor { Gfx::StandardCursor::None };
 };
 
 }
diff --git a/Userland/Libraries/LibGUI/Action.cpp b/Userland/Libraries/LibGUI/Action.cpp
index 07fbdb41f7d..04a34d1a1b8 100644
--- a/Userland/Libraries/LibGUI/Action.cpp
+++ b/Userland/Libraries/LibGUI/Action.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -18,7 +18,7 @@ NonnullRefPtr<Action> Action::create(DeprecatedString text, Function<void(Action
     return adopt_ref(*new Action(move(text), move(callback), parent));
 }
 
-NonnullRefPtr<Action> Action::create(DeprecatedString text, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent)
+NonnullRefPtr<Action> Action::create(DeprecatedString text, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent)
 {
     return adopt_ref(*new Action(move(text), move(icon), move(callback), parent));
 }
@@ -33,12 +33,12 @@ NonnullRefPtr<Action> Action::create(DeprecatedString text, Shortcut const& shor
     return adopt_ref(*new Action(move(text), shortcut, alternate_shortcut, move(callback), parent));
 }
 
-NonnullRefPtr<Action> Action::create(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent)
+NonnullRefPtr<Action> Action::create(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent)
 {
     return adopt_ref(*new Action(move(text), shortcut, Shortcut {}, move(icon), move(callback), parent));
 }
 
-NonnullRefPtr<Action> Action::create(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent)
+NonnullRefPtr<Action> Action::create(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent)
 {
     return adopt_ref(*new Action(move(text), shortcut, alternate_shortcut, move(icon), move(callback), parent));
 }
@@ -48,7 +48,7 @@ NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, Function<v
     return adopt_ref(*new Action(move(text), move(callback), parent, true));
 }
 
-NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent)
+NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent)
 {
     return adopt_ref(*new Action(move(text), move(icon), move(callback), parent, true));
 }
@@ -58,7 +58,7 @@ NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, Shortcut c
     return adopt_ref(*new Action(move(text), shortcut, move(callback), parent, true));
 }
 
-NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent)
+NonnullRefPtr<Action> Action::create_checkable(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent)
 {
     return adopt_ref(*new Action(move(text), shortcut, Shortcut {}, move(icon), move(callback), parent, true));
 }
@@ -86,7 +86,7 @@ Action::Action(DeprecatedString text, Function<void(Action&)> on_activation_call
 {
 }
 
-Action::Action(DeprecatedString text, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> on_activation_callback, Core::Object* parent, bool checkable)
+Action::Action(DeprecatedString text, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> on_activation_callback, Core::Object* parent, bool checkable)
     : Action(move(text), Shortcut {}, Shortcut {}, move(icon), move(on_activation_callback), parent, checkable)
 {
 }
@@ -101,7 +101,7 @@ Action::Action(DeprecatedString text, Shortcut const& shortcut, Shortcut const&
 {
 }
 
-Action::Action(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> on_activation_callback, Core::Object* parent, bool checkable)
+Action::Action(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> on_activation_callback, Core::Object* parent, bool checkable)
     : Core::Object(parent)
     , on_activation(move(on_activation_callback))
     , m_text(move(text))
diff --git a/Userland/Libraries/LibGUI/Action.h b/Userland/Libraries/LibGUI/Action.h
index f5e615048c3..8225977b7ca 100644
--- a/Userland/Libraries/LibGUI/Action.h
+++ b/Userland/Libraries/LibGUI/Action.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -66,15 +66,15 @@ public:
         ApplicationGlobal,
     };
     static NonnullRefPtr<Action> create(DeprecatedString text, Function<void(Action&)> callback, Core::Object* parent = nullptr);
-    static NonnullRefPtr<Action> create(DeprecatedString text, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
+    static NonnullRefPtr<Action> create(DeprecatedString text, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
     static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, Function<void(Action&)> callback, Core::Object* parent = nullptr);
     static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, Function<void(Action&)> callback, Core::Object* parent = nullptr);
-    static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
-    static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
+    static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
+    static NonnullRefPtr<Action> create(DeprecatedString text, Shortcut const& shortcut, Shortcut const& alternate_shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
     static NonnullRefPtr<Action> create_checkable(DeprecatedString text, Function<void(Action&)> callback, Core::Object* parent = nullptr);
-    static NonnullRefPtr<Action> create_checkable(DeprecatedString text, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
+    static NonnullRefPtr<Action> create_checkable(DeprecatedString text, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
     static NonnullRefPtr<Action> create_checkable(DeprecatedString text, Shortcut const& shortcut, Function<void(Action&)> callback, Core::Object* parent = nullptr);
-    static NonnullRefPtr<Action> create_checkable(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
+    static NonnullRefPtr<Action> create_checkable(DeprecatedString text, Shortcut const& shortcut, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> callback, Core::Object* parent = nullptr);
 
     static ErrorOr<NonnullRefPtr<Action>> try_create_checkable(DeprecatedString text, Shortcut const& shortcut, Function<void(Action&)> callback, Core::Object* parent = nullptr);
 
@@ -135,8 +135,8 @@ private:
     Action(DeprecatedString, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
     Action(DeprecatedString, Shortcut const&, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
     Action(DeprecatedString, Shortcut const&, Shortcut const&, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
-    Action(DeprecatedString, Shortcut const&, Shortcut const&, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
-    Action(DeprecatedString, RefPtr<Gfx::Bitmap> icon, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
+    Action(DeprecatedString, Shortcut const&, Shortcut const&, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
+    Action(DeprecatedString, RefPtr<Gfx::Bitmap const> icon, Function<void(Action&)> = nullptr, Core::Object* = nullptr, bool checkable = false);
 
     template<typename Callback>
     void for_each_toolbar_button(Callback);
@@ -145,7 +145,7 @@ private:
 
     DeprecatedString m_text;
     DeprecatedString m_status_tip;
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     Shortcut m_shortcut;
     Shortcut m_alternate_shortcut;
     bool m_enabled { true };
diff --git a/Userland/Libraries/LibGUI/Application.cpp b/Userland/Libraries/LibGUI/Application.cpp
index 1abb2074369..7fc73b965b8 100644
--- a/Userland/Libraries/LibGUI/Application.cpp
+++ b/Userland/Libraries/LibGUI/Application.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -211,7 +211,7 @@ void Application::set_system_palette(Core::AnonymousBuffer& buffer)
         m_palette = m_system_palette;
 }
 
-void Application::set_palette(Palette const& palette)
+void Application::set_palette(Palette& palette)
 {
     m_palette = palette.impl();
 }
diff --git a/Userland/Libraries/LibGUI/Application.h b/Userland/Libraries/LibGUI/Application.h
index b538f14f1e6..5f03f68cf4f 100644
--- a/Userland/Libraries/LibGUI/Application.h
+++ b/Userland/Libraries/LibGUI/Application.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -41,7 +41,7 @@ public:
     void show_tooltip(DeprecatedString, Widget const* tooltip_source_widget);
     void show_tooltip_immediately(DeprecatedString, Widget const* tooltip_source_widget);
     void hide_tooltip();
-    Widget* tooltip_source_widget() { return m_tooltip_source_widget; };
+    Widget const* tooltip_source_widget() { return m_tooltip_source_widget; };
 
     bool quit_when_last_window_deleted() const { return m_quit_when_last_window_deleted; }
     void set_quit_when_last_window_deleted(bool b) { m_quit_when_last_window_deleted = b; }
@@ -53,7 +53,7 @@ public:
     Vector<DeprecatedString> const& args() const { return m_args; }
 
     Gfx::Palette palette() const;
-    void set_palette(Gfx::Palette const&);
+    void set_palette(Gfx::Palette&);
 
     void set_system_palette(Core::AnonymousBuffer&);
 
@@ -110,7 +110,7 @@ private:
     RefPtr<Core::Timer> m_tooltip_show_timer;
     RefPtr<Core::Timer> m_tooltip_hide_timer;
     RefPtr<TooltipWindow> m_tooltip_window;
-    RefPtr<Widget> m_tooltip_source_widget;
+    RefPtr<Widget const> m_tooltip_source_widget;
     WeakPtr<Window> m_active_window;
     bool m_quit_when_last_window_deleted { true };
     bool m_focus_debugging_enabled { false };
diff --git a/Userland/Libraries/LibGUI/Button.cpp b/Userland/Libraries/LibGUI/Button.cpp
index e75938da564..87913e6c15c 100644
--- a/Userland/Libraries/LibGUI/Button.cpp
+++ b/Userland/Libraries/LibGUI/Button.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -178,7 +178,7 @@ void Button::set_action(Action& action)
         set_checked(action.is_checked());
 }
 
-void Button::set_icon(RefPtr<Gfx::Bitmap> icon)
+void Button::set_icon(RefPtr<Gfx::Bitmap const> icon)
 {
     if (m_icon == icon)
         return;
diff --git a/Userland/Libraries/LibGUI/Button.h b/Userland/Libraries/LibGUI/Button.h
index b91f92ad972..69365179631 100644
--- a/Userland/Libraries/LibGUI/Button.h
+++ b/Userland/Libraries/LibGUI/Button.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -28,10 +28,9 @@ public:
 
     virtual ~Button() override;
 
-    void set_icon(RefPtr<Gfx::Bitmap>);
+    void set_icon(RefPtr<Gfx::Bitmap const>);
     void set_icon_from_path(DeprecatedString const&);
     Gfx::Bitmap const* icon() const { return m_icon.ptr(); }
-    Gfx::Bitmap* icon() { return m_icon.ptr(); }
 
     void set_text_alignment(Gfx::TextAlignment text_alignment) { m_text_alignment = text_alignment; }
     Gfx::TextAlignment text_alignment() const { return m_text_alignment; }
@@ -78,7 +77,7 @@ protected:
 private:
     virtual void timer_event(Core::TimerEvent&) override;
 
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     RefPtr<GUI::Menu> m_menu;
     Gfx::ButtonStyle m_button_style { Gfx::ButtonStyle::Normal };
     Gfx::TextAlignment m_text_alignment { Gfx::TextAlignment::Center };
diff --git a/Userland/Libraries/LibGUI/Desktop.cpp b/Userland/Libraries/LibGUI/Desktop.cpp
index 19ae39f5539..980c6fdff60 100644
--- a/Userland/Libraries/LibGUI/Desktop.cpp
+++ b/Userland/Libraries/LibGUI/Desktop.cpp
@@ -59,7 +59,7 @@ RefPtr<Gfx::Bitmap> Desktop::wallpaper_bitmap() const
     return ConnectionToWindowServer::the().get_wallpaper().bitmap();
 }
 
-bool Desktop::set_wallpaper(RefPtr<Gfx::Bitmap> wallpaper_bitmap, Optional<DeprecatedString> path)
+bool Desktop::set_wallpaper(RefPtr<Gfx::Bitmap const> wallpaper_bitmap, Optional<DeprecatedString> path)
 {
     if (m_is_setting_desktop_wallpaper)
         return false;
diff --git a/Userland/Libraries/LibGUI/Desktop.h b/Userland/Libraries/LibGUI/Desktop.h
index fd2c2726ed4..e1e18065c32 100644
--- a/Userland/Libraries/LibGUI/Desktop.h
+++ b/Userland/Libraries/LibGUI/Desktop.h
@@ -33,7 +33,7 @@ public:
 
     DeprecatedString wallpaper_path() const;
     RefPtr<Gfx::Bitmap> wallpaper_bitmap() const;
-    bool set_wallpaper(RefPtr<Gfx::Bitmap> wallpaper_bitmap, Optional<DeprecatedString> path);
+    bool set_wallpaper(RefPtr<Gfx::Bitmap const> wallpaper_bitmap, Optional<DeprecatedString> path);
 
     void set_system_effects(Vector<bool> effects) { m_system_effects = { effects }; };
     SystemEffects const& system_effects() const { return m_system_effects; }
diff --git a/Userland/Libraries/LibGUI/EmojiInputDialog.cpp b/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
index b0a12d8777a..c4f694afb8b 100644
--- a/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
+++ b/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -46,7 +46,7 @@ static constexpr auto s_emoji_groups = Array {
     EmojiCateogry { Unicode::EmojiGroup::SerenityOS, 0x10CD0B },
 };
 
-static void resize_bitmap_if_needed(RefPtr<Gfx::Bitmap>& bitmap)
+static void resize_bitmap_if_needed(RefPtr<Gfx::Bitmap const>& bitmap)
 {
     constexpr int max_icon_size = 12;
 
@@ -74,7 +74,7 @@ private:
         if (m_first_paint_event) {
             m_first_paint_event = false;
 
-            RefPtr<Gfx::Bitmap> bitmap = Gfx::Emoji::emoji_for_code_points(m_emoji_code_points);
+            RefPtr<Gfx::Bitmap const> bitmap = Gfx::Emoji::emoji_for_code_points(m_emoji_code_points);
             VERIFY(bitmap);
 
             resize_bitmap_if_needed(bitmap);
@@ -113,7 +113,7 @@ EmojiInputDialog::EmojiInputDialog(Window* parent_window)
         auto name = Unicode::emoji_group_to_string(category.group);
         auto tooltip = name.replace("&"sv, "&&"sv, ReplaceMode::FirstOnly);
 
-        RefPtr<Gfx::Bitmap> bitmap = Gfx::Emoji::emoji_for_code_point(category.emoji_code_point);
+        RefPtr<Gfx::Bitmap const> bitmap = Gfx::Emoji::emoji_for_code_point(category.emoji_code_point);
         VERIFY(bitmap);
         resize_bitmap_if_needed(bitmap);
 
diff --git a/Userland/Libraries/LibGUI/Event.cpp b/Userland/Libraries/LibGUI/Event.cpp
index c109b09519d..549e393f811 100644
--- a/Userland/Libraries/LibGUI/Event.cpp
+++ b/Userland/Libraries/LibGUI/Event.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -12,7 +12,7 @@
 
 namespace GUI {
 
-DropEvent::DropEvent(Gfx::IntPoint position, DeprecatedString const& text, NonnullRefPtr<Core::MimeData> mime_data)
+DropEvent::DropEvent(Gfx::IntPoint position, DeprecatedString const& text, NonnullRefPtr<Core::MimeData const> mime_data)
     : Event(Event::Drop)
     , m_position(position)
     , m_text(text)
diff --git a/Userland/Libraries/LibGUI/Event.h b/Userland/Libraries/LibGUI/Event.h
index 9b64b72b042..1902889a062 100644
--- a/Userland/Libraries/LibGUI/Event.h
+++ b/Userland/Libraries/LibGUI/Event.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -229,7 +229,7 @@ public:
     Gfx::Bitmap const* bitmap() const { return m_bitmap; }
 
 private:
-    RefPtr<Gfx::Bitmap> m_bitmap;
+    RefPtr<Gfx::Bitmap const> m_bitmap;
 };
 
 class WMWorkspaceChangedEvent : public WMEvent {
@@ -477,7 +477,7 @@ private:
 
 class DropEvent final : public Event {
 public:
-    DropEvent(Gfx::IntPoint, DeprecatedString const& text, NonnullRefPtr<Core::MimeData> mime_data);
+    DropEvent(Gfx::IntPoint, DeprecatedString const& text, NonnullRefPtr<Core::MimeData const> mime_data);
 
     ~DropEvent() = default;
 
@@ -488,7 +488,7 @@ public:
 private:
     Gfx::IntPoint m_position;
     DeprecatedString m_text;
-    NonnullRefPtr<Core::MimeData> m_mime_data;
+    NonnullRefPtr<Core::MimeData const> m_mime_data;
 };
 
 class ThemeChangeEvent final : public Event {
diff --git a/Userland/Libraries/LibGUI/FileIconProvider.cpp b/Userland/Libraries/LibGUI/FileIconProvider.cpp
index 74a331b1035..d0f603ac75e 100644
--- a/Userland/Libraries/LibGUI/FileIconProvider.cpp
+++ b/Userland/Libraries/LibGUI/FileIconProvider.cpp
@@ -205,7 +205,7 @@ Icon FileIconProvider::icon_for_executable(DeprecatedString const& path)
     for (auto const& icon_section : icon_sections) {
         auto section = image.lookup_section(icon_section.section_name);
 
-        RefPtr<Gfx::Bitmap> bitmap;
+        RefPtr<Gfx::Bitmap const> bitmap;
         if (!section.has_value()) {
             bitmap = s_executable_icon.bitmap_for_size(icon_section.image_size);
         } else {
diff --git a/Userland/Libraries/LibGUI/FontPicker.h b/Userland/Libraries/LibGUI/FontPicker.h
index 2d3e4d15fb3..96d500839fb 100644
--- a/Userland/Libraries/LibGUI/FontPicker.h
+++ b/Userland/Libraries/LibGUI/FontPicker.h
@@ -19,7 +19,7 @@ class FontPicker final : public GUI::Dialog {
 public:
     virtual ~FontPicker() override = default;
 
-    RefPtr<Gfx::Font> font() const { return m_font; }
+    RefPtr<Gfx::Font const> font() const { return m_font; }
     void set_font(Gfx::Font const*);
 
 private:
@@ -29,7 +29,7 @@ private:
 
     bool const m_fixed_width_only;
 
-    RefPtr<Gfx::Font> m_font;
+    RefPtr<Gfx::Font const> m_font;
 
     RefPtr<ListView> m_family_list_view;
     RefPtr<ListView> m_variant_list_view;
diff --git a/Userland/Libraries/LibGUI/GML/AST.h b/Userland/Libraries/LibGUI/GML/AST.h
index 9c8d8acd309..dded956b395 100644
--- a/Userland/Libraries/LibGUI/GML/AST.h
+++ b/Userland/Libraries/LibGUI/GML/AST.h
@@ -152,7 +152,7 @@ public:
 class Object : public ValueNode {
 public:
     Object() = default;
-    Object(DeprecatedString name, NonnullRefPtrVector<Node> properties, NonnullRefPtrVector<Node> sub_objects)
+    Object(DeprecatedString name, NonnullRefPtrVector<Node const> properties, NonnullRefPtrVector<Node const> sub_objects)
         : m_properties(move(properties))
         , m_sub_objects(move(sub_objects))
         , m_name(move(name))
@@ -164,13 +164,13 @@ public:
     StringView name() const { return m_name; }
     void set_name(DeprecatedString name) { m_name = move(name); }
 
-    ErrorOr<void> add_sub_object_child(NonnullRefPtr<Node> child)
+    ErrorOr<void> add_sub_object_child(NonnullRefPtr<Node const> child)
     {
         VERIFY(is<Object>(child.ptr()) || is<Comment>(child.ptr()));
         return m_sub_objects.try_append(move(child));
     }
 
-    ErrorOr<void> add_property_child(NonnullRefPtr<Node> child)
+    ErrorOr<void> add_property_child(NonnullRefPtr<Node const> child)
     {
         VERIFY(is<KeyValuePair>(child.ptr()) || is<Comment>(child.ptr()));
         return m_properties.try_append(move(child));
@@ -178,7 +178,7 @@ public:
 
     // Does not return key-value pair `layout: ...`!
     template<typename Callback>
-    void for_each_property(Callback callback)
+    void for_each_property(Callback callback) const
     {
         for (auto const& child : m_properties) {
             if (is<KeyValuePair>(child)) {
@@ -190,52 +190,51 @@ public:
     }
 
     template<typename Callback>
-    void for_each_child_object(Callback callback)
+    void for_each_child_object(Callback callback) const
     {
-        for (NonnullRefPtr<Node> child : m_sub_objects) {
+        for (NonnullRefPtr<Node const> child : m_sub_objects) {
             // doesn't capture layout as intended, as that's behind a kv-pair
             if (is<Object>(child.ptr())) {
-                auto object = static_ptr_cast<Object>(child);
+                auto object = static_ptr_cast<Object const>(child);
                 callback(object);
             }
         }
     }
 
     template<FallibleFunction<NonnullRefPtr<Object>> Callback>
-    ErrorOr<void> try_for_each_child_object(Callback callback)
+    ErrorOr<void> try_for_each_child_object(Callback callback) const
     {
-        for (NonnullRefPtr<Node> child : m_sub_objects) {
+        for (auto const& child : m_sub_objects) {
             // doesn't capture layout as intended, as that's behind a kv-pair
-            if (is<Object>(child.ptr())) {
-                auto object = static_ptr_cast<Object>(child);
-                TRY(callback(object));
+            if (is<Object>(child)) {
+                TRY(callback(static_cast<Object const&>(child)));
             }
         }
 
         return {};
     }
 
-    RefPtr<Object> layout_object() const
+    RefPtr<Object const> layout_object() const
     {
-        for (NonnullRefPtr<Node> child : m_properties) {
-            if (is<KeyValuePair>(child.ptr())) {
-                auto property = static_ptr_cast<KeyValuePair>(child);
-                if (property->key() == "layout") {
-                    VERIFY(is<Object>(property->value().ptr()));
-                    return static_ptr_cast<Object>(property->value());
+        for (auto const& child : m_properties) {
+            if (is<KeyValuePair>(child)) {
+                auto const& property = static_cast<KeyValuePair const&>(child);
+                if (property.key() == "layout") {
+                    VERIFY(is<Object>(property.value().ptr()));
+                    return static_cast<Object const&>(*property.value());
                 }
             }
         }
         return nullptr;
     }
 
-    RefPtr<ValueNode> get_property(StringView property_name)
+    RefPtr<ValueNode const> get_property(StringView property_name) const
     {
-        for (NonnullRefPtr<Node> child : m_properties) {
-            if (is<KeyValuePair>(child.ptr())) {
-                auto property = static_ptr_cast<KeyValuePair>(child);
-                if (property->key() == property_name)
-                    return property->value();
+        for (auto const& child : m_properties) {
+            if (is<KeyValuePair>(child)) {
+                auto const& property = static_cast<KeyValuePair const&>(child);
+                if (property.key() == property_name)
+                    return property.value();
             }
         }
         return nullptr;
@@ -275,9 +274,9 @@ public:
 
 private:
     // Properties and comments
-    NonnullRefPtrVector<Node> m_properties;
+    NonnullRefPtrVector<Node const> m_properties;
     // Sub objects and comments
-    NonnullRefPtrVector<Node> m_sub_objects;
+    NonnullRefPtrVector<Node const> m_sub_objects;
     DeprecatedString m_name {};
 };
 
@@ -285,14 +284,14 @@ class GMLFile : public Node {
 public:
     virtual ~GMLFile() override = default;
 
-    ErrorOr<void> add_child(NonnullRefPtr<Node> child)
+    ErrorOr<void> add_child(NonnullRefPtr<Node const> child)
     {
         if (!has_main_class()) {
             if (is<Comment>(child.ptr())) {
-                return m_leading_comments.try_append(*static_ptr_cast<Comment>(child));
+                return m_leading_comments.try_append(*static_ptr_cast<Comment const>(child));
             }
             if (is<Object>(child.ptr())) {
-                m_main_class = static_ptr_cast<Object>(child);
+                m_main_class = static_ptr_cast<Object const>(child);
                 return {};
             }
             return Error::from_string_literal("Unexpected data before main class");
@@ -300,18 +299,18 @@ public:
         // After the main class, only comments are allowed.
         if (!is<Comment>(child.ptr()))
             return Error::from_string_literal("Data not allowed after main class");
-        return m_trailing_comments.try_append(*static_ptr_cast<Comment>(child));
+        return m_trailing_comments.try_append(*static_ptr_cast<Comment const>(child));
     }
 
     bool has_main_class() const { return m_main_class != nullptr; }
 
-    NonnullRefPtrVector<Comment> leading_comments() const { return m_leading_comments; }
-    Object& main_class()
+    NonnullRefPtrVector<Comment const> leading_comments() const { return m_leading_comments; }
+    Object const& main_class() const
     {
         VERIFY(!m_main_class.is_null());
         return *m_main_class.ptr();
     }
-    NonnullRefPtrVector<Comment> trailing_comments() const { return m_trailing_comments; }
+    NonnullRefPtrVector<Comment const> trailing_comments() const { return m_trailing_comments; }
 
     virtual void format(StringBuilder& builder, size_t indentation, [[maybe_unused]] bool is_inline) const override
     {
@@ -329,9 +328,9 @@ public:
     }
 
 private:
-    NonnullRefPtrVector<Comment> m_leading_comments;
-    RefPtr<Object> m_main_class;
-    NonnullRefPtrVector<Comment> m_trailing_comments;
+    NonnullRefPtrVector<Comment const> m_leading_comments;
+    RefPtr<Object const> m_main_class;
+    NonnullRefPtrVector<Comment const> m_trailing_comments;
 };
 
 }
diff --git a/Userland/Libraries/LibGUI/GML/Parser.cpp b/Userland/Libraries/LibGUI/GML/Parser.cpp
index 270bf984dde..18f93109f4c 100644
--- a/Userland/Libraries/LibGUI/GML/Parser.cpp
+++ b/Userland/Libraries/LibGUI/GML/Parser.cpp
@@ -82,7 +82,7 @@ static ErrorOr<NonnullRefPtr<Object>> parse_gml_object(Queue<Token>& tokens)
                 else if (peek() == Token::Type::JsonValue)
                     value = TRY(try_make_ref_counted<JsonValueNode>(TRY(JsonValueNode::from_string(tokens.dequeue().m_view))));
 
-                auto property = TRY(try_make_ref_counted<KeyValuePair>(property_name.m_view, value.release_nonnull()));
+                auto property = TRY(try_make_ref_counted<KeyValuePair const>(property_name.m_view, value.release_nonnull()));
                 TRY(object->add_property_child(property));
             } else if (peek() == Token::Type::Comment) {
                 pending_comments.append(TRY(Node::from_token<Comment>(tokens.dequeue())));
diff --git a/Userland/Libraries/LibGUI/Icon.cpp b/Userland/Libraries/LibGUI/Icon.cpp
index fd9c5575f5e..e2a8c6637aa 100644
--- a/Userland/Libraries/LibGUI/Icon.cpp
+++ b/Userland/Libraries/LibGUI/Icon.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Julius Heijmen <julius.heijmen@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -26,7 +26,7 @@ Icon::Icon(Icon const& other)
 {
 }
 
-Icon::Icon(RefPtr<Gfx::Bitmap>&& bitmap)
+Icon::Icon(RefPtr<Gfx::Bitmap const>&& bitmap)
     : Icon()
 {
     if (bitmap) {
@@ -36,7 +36,7 @@ Icon::Icon(RefPtr<Gfx::Bitmap>&& bitmap)
     }
 }
 
-Icon::Icon(RefPtr<Gfx::Bitmap>&& bitmap1, RefPtr<Gfx::Bitmap>&& bitmap2)
+Icon::Icon(RefPtr<Gfx::Bitmap const>&& bitmap1, RefPtr<Gfx::Bitmap const>&& bitmap2)
     : Icon(move(bitmap1))
 {
     if (bitmap2) {
@@ -64,7 +64,7 @@ Gfx::Bitmap const* IconImpl::bitmap_for_size(int size) const
     return best_fit;
 }
 
-void IconImpl::set_bitmap_for_size(int size, RefPtr<Gfx::Bitmap>&& bitmap)
+void IconImpl::set_bitmap_for_size(int size, RefPtr<Gfx::Bitmap const>&& bitmap)
 {
     if (!bitmap) {
         m_bitmaps.remove(size);
diff --git a/Userland/Libraries/LibGUI/Icon.h b/Userland/Libraries/LibGUI/Icon.h
index b11cbcf42be..111e0cf7bab 100644
--- a/Userland/Libraries/LibGUI/Icon.h
+++ b/Userland/Libraries/LibGUI/Icon.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Julius Heijmen <julius.heijmen@gmail.com>
  * Copyright (c) 2022, the SerenityOS developers.
  *
@@ -21,7 +21,7 @@ public:
     ~IconImpl() = default;
 
     Gfx::Bitmap const* bitmap_for_size(int) const;
-    void set_bitmap_for_size(int, RefPtr<Gfx::Bitmap>&&);
+    void set_bitmap_for_size(int, RefPtr<Gfx::Bitmap const>&&);
 
     Vector<int> sizes() const
     {
@@ -33,14 +33,14 @@ public:
 
 private:
     IconImpl() = default;
-    HashMap<int, RefPtr<Gfx::Bitmap>> m_bitmaps;
+    HashMap<int, RefPtr<Gfx::Bitmap const>> m_bitmaps;
 };
 
 class Icon {
 public:
     Icon();
-    explicit Icon(RefPtr<Gfx::Bitmap>&&);
-    explicit Icon(RefPtr<Gfx::Bitmap>&&, RefPtr<Gfx::Bitmap>&&);
+    explicit Icon(RefPtr<Gfx::Bitmap const>&&);
+    explicit Icon(RefPtr<Gfx::Bitmap const>&&, RefPtr<Gfx::Bitmap const>&&);
     explicit Icon(IconImpl const&);
     Icon(Icon const&);
     ~Icon() = default;
@@ -56,7 +56,7 @@ public:
     }
 
     Gfx::Bitmap const* bitmap_for_size(int size) const { return m_impl->bitmap_for_size(size); }
-    void set_bitmap_for_size(int size, RefPtr<Gfx::Bitmap>&& bitmap) { m_impl->set_bitmap_for_size(size, move(bitmap)); }
+    void set_bitmap_for_size(int size, RefPtr<Gfx::Bitmap const>&& bitmap) { m_impl->set_bitmap_for_size(size, move(bitmap)); }
 
     IconImpl const& impl() const { return *m_impl; }
 
diff --git a/Userland/Libraries/LibGUI/ImageWidget.h b/Userland/Libraries/LibGUI/ImageWidget.h
index 80669ee51bf..967bb192471 100644
--- a/Userland/Libraries/LibGUI/ImageWidget.h
+++ b/Userland/Libraries/LibGUI/ImageWidget.h
@@ -19,7 +19,6 @@ public:
     virtual ~ImageWidget() override = default;
 
     void set_bitmap(Gfx::Bitmap const*);
-    Gfx::Bitmap* bitmap() { return m_bitmap.ptr(); }
     Gfx::Bitmap const* bitmap() const { return m_bitmap.ptr(); }
 
     void set_should_stretch(bool value) { m_should_stretch = value; }
@@ -43,7 +42,7 @@ protected:
     virtual void paint_event(PaintEvent&) override;
 
 private:
-    RefPtr<Gfx::Bitmap> m_bitmap;
+    RefPtr<Gfx::Bitmap const> m_bitmap;
     bool m_should_stretch { false };
     bool m_auto_resize { false };
 
diff --git a/Userland/Libraries/LibGUI/Label.h b/Userland/Libraries/LibGUI/Label.h
index d7c915c5ab3..a80217ba300 100644
--- a/Userland/Libraries/LibGUI/Label.h
+++ b/Userland/Libraries/LibGUI/Label.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -25,7 +25,6 @@ public:
     void set_icon(Gfx::Bitmap const*);
     void set_icon_from_path(DeprecatedString const&);
     Gfx::Bitmap const* icon() const { return m_icon.ptr(); }
-    Gfx::Bitmap* icon() { return m_icon.ptr(); }
 
     Gfx::TextAlignment text_alignment() const { return m_text_alignment; }
     void set_text_alignment(Gfx::TextAlignment text_alignment) { m_text_alignment = text_alignment; }
@@ -54,7 +53,7 @@ private:
     void size_to_fit();
 
     DeprecatedString m_text;
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     Gfx::TextAlignment m_text_alignment { Gfx::TextAlignment::Center };
     Gfx::TextWrapping m_text_wrapping { Gfx::TextWrapping::Wrap };
     bool m_should_stretch_icon { false };
diff --git a/Userland/Libraries/LibGUI/Menu.h b/Userland/Libraries/LibGUI/Menu.h
index 7f0da099378..f95b7db9898 100644
--- a/Userland/Libraries/LibGUI/Menu.h
+++ b/Userland/Libraries/LibGUI/Menu.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -74,7 +74,7 @@ private:
 
     int m_menu_id { -1 };
     DeprecatedString m_name;
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     NonnullOwnPtrVector<MenuItem> m_items;
     WeakPtr<Action> m_current_default_action;
     bool m_visible { false };
diff --git a/Userland/Libraries/LibGUI/Model.cpp b/Userland/Libraries/LibGUI/Model.cpp
index 401c76b98cb..8280093b92a 100644
--- a/Userland/Libraries/LibGUI/Model.cpp
+++ b/Userland/Libraries/LibGUI/Model.cpp
@@ -100,7 +100,7 @@ WeakPtr<PersistentHandle> Model::register_persistent_index(Badge<PersistentModel
 RefPtr<Core::MimeData> Model::mime_data(ModelSelection const& selection) const
 {
     auto mime_data = Core::MimeData::construct();
-    RefPtr<Gfx::Bitmap> bitmap;
+    RefPtr<Gfx::Bitmap const> bitmap;
 
     StringBuilder text_builder;
     StringBuilder data_builder;
diff --git a/Userland/Libraries/LibGUI/Notification.h b/Userland/Libraries/LibGUI/Notification.h
index 42fac9fbe55..b5f200c9cb7 100644
--- a/Userland/Libraries/LibGUI/Notification.h
+++ b/Userland/Libraries/LibGUI/Notification.h
@@ -57,7 +57,7 @@ private:
     bool m_title_dirty;
     DeprecatedString m_text;
     bool m_text_dirty;
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     bool m_icon_dirty;
 
     bool m_destroyed { false };
diff --git a/Userland/Libraries/LibGUI/ProcessChooser.h b/Userland/Libraries/LibGUI/ProcessChooser.h
index 5c7e79eef37..64e67a7292d 100644
--- a/Userland/Libraries/LibGUI/ProcessChooser.h
+++ b/Userland/Libraries/LibGUI/ProcessChooser.h
@@ -31,7 +31,7 @@ private:
 
     DeprecatedString m_window_title;
     String m_button_label;
-    RefPtr<Gfx::Bitmap> m_window_icon;
+    RefPtr<Gfx::Bitmap const> m_window_icon;
     RefPtr<TableView> m_table_view;
     RefPtr<RunningProcessesModel> m_process_model;
 
diff --git a/Userland/Libraries/LibGUI/RunningProcessesModel.h b/Userland/Libraries/LibGUI/RunningProcessesModel.h
index 43fbaaef50d..9d0fe48e778 100644
--- a/Userland/Libraries/LibGUI/RunningProcessesModel.h
+++ b/Userland/Libraries/LibGUI/RunningProcessesModel.h
@@ -38,7 +38,7 @@ private:
     struct Process {
         pid_t pid;
         uid_t uid;
-        RefPtr<Gfx::Bitmap> icon;
+        RefPtr<Gfx::Bitmap const> icon;
         DeprecatedString name;
     };
     Vector<Process> m_processes;
diff --git a/Userland/Libraries/LibGUI/ScrollableContainerWidget.cpp b/Userland/Libraries/LibGUI/ScrollableContainerWidget.cpp
index f7110fb9889..9ecb198e7db 100644
--- a/Userland/Libraries/LibGUI/ScrollableContainerWidget.cpp
+++ b/Userland/Libraries/LibGUI/ScrollableContainerWidget.cpp
@@ -102,32 +102,32 @@ void ScrollableContainerWidget::set_widget(GUI::Widget* widget)
     update_widget_position();
 }
 
-ErrorOr<void> ScrollableContainerWidget::load_from_gml_ast(NonnullRefPtr<GUI::GML::Node> ast, UnregisteredChildHandler unregistered_child_handler)
+ErrorOr<void> ScrollableContainerWidget::load_from_gml_ast(NonnullRefPtr<GUI::GML::Node const> ast, UnregisteredChildHandler unregistered_child_handler)
 {
     if (is<GUI::GML::GMLFile>(ast.ptr()))
-        return load_from_gml_ast(static_ptr_cast<GUI::GML::GMLFile>(ast)->main_class(), unregistered_child_handler);
+        return load_from_gml_ast(static_cast<GUI::GML::GMLFile const&>(*ast).main_class(), unregistered_child_handler);
 
     VERIFY(is<GUI::GML::Object>(ast.ptr()));
-    auto object = static_ptr_cast<GUI::GML::Object>(ast);
+    auto const& object = static_cast<GUI::GML::Object const&>(*ast);
 
-    object->for_each_property([&](auto key, auto value) {
+    object.for_each_property([&](auto key, auto value) {
         set_property(key, value);
     });
 
-    auto content_widget_value = object->get_property("content_widget"sv);
+    auto content_widget_value = object.get_property("content_widget"sv);
     if (!content_widget_value.is_null() && !is<GUI::GML::Object>(content_widget_value.ptr())) {
         return Error::from_string_literal("ScrollableContainerWidget content_widget is not an object");
     }
 
     auto has_children = false;
-    object->for_each_child_object([&](auto) { has_children = true; });
+    object.for_each_child_object([&](auto) { has_children = true; });
     if (has_children) {
         return Error::from_string_literal("Children specified for ScrollableContainerWidget, but only 1 widget as content_widget is supported");
     }
 
     if (!content_widget_value.is_null() && is<GUI::GML::Object>(content_widget_value.ptr())) {
-        auto content_widget = static_ptr_cast<GUI::GML::Object>(content_widget_value);
-        auto class_name = content_widget->name();
+        auto const& content_widget = static_cast<GUI::GML::Object const&>(*content_widget_value);
+        auto class_name = content_widget.name();
 
         RefPtr<Core::Object> child;
         if (auto* registration = Core::ObjectClassRegistration::find(class_name)) {
@@ -139,7 +139,7 @@ ErrorOr<void> ScrollableContainerWidget::load_from_gml_ast(NonnullRefPtr<GUI::GM
             return Error::from_string_literal("Unable to construct a Widget class for ScrollableContainerWidget content_widget property");
         auto widget_ptr = verify_cast<GUI::Widget>(child.ptr());
         set_widget(widget_ptr);
-        TRY(static_ptr_cast<Widget>(child)->load_from_gml_ast(content_widget.release_nonnull(), unregistered_child_handler));
+        TRY(static_cast<Widget&>(*child).load_from_gml_ast(content_widget, unregistered_child_handler));
     }
 
     return {};
diff --git a/Userland/Libraries/LibGUI/ScrollableContainerWidget.h b/Userland/Libraries/LibGUI/ScrollableContainerWidget.h
index ef0e4e7ac97..0b6f2f5ea23 100644
--- a/Userland/Libraries/LibGUI/ScrollableContainerWidget.h
+++ b/Userland/Libraries/LibGUI/ScrollableContainerWidget.h
@@ -30,7 +30,7 @@ private:
     void update_widget_size();
     void update_widget_position();
     void update_widget_min_size();
-    virtual ErrorOr<void> load_from_gml_ast(NonnullRefPtr<GUI::GML::Node> ast, UnregisteredChildHandler) override;
+    virtual ErrorOr<void> load_from_gml_ast(NonnullRefPtr<GUI::GML::Node const> ast, UnregisteredChildHandler) override;
 
     ScrollableContainerWidget();
 
diff --git a/Userland/Libraries/LibGUI/TabWidget.cpp b/Userland/Libraries/LibGUI/TabWidget.cpp
index 4e3301f196e..4c068b994f4 100644
--- a/Userland/Libraries/LibGUI/TabWidget.cpp
+++ b/Userland/Libraries/LibGUI/TabWidget.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Peter Elliott <pelliott@serenityos.org>
  * Copyright (c) 2022, Cameron Youell <cameronyouell@gmail.com>
  * Copyright (c) 2022, the SerenityOS developers.
diff --git a/Userland/Libraries/LibGUI/TabWidget.h b/Userland/Libraries/LibGUI/TabWidget.h
index 835d29d04ba..9e18e51403e 100644
--- a/Userland/Libraries/LibGUI/TabWidget.h
+++ b/Userland/Libraries/LibGUI/TabWidget.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -148,7 +148,7 @@ private:
     struct TabData {
         int width(Gfx::Font const&) const;
         DeprecatedString title;
-        RefPtr<Gfx::Bitmap> icon;
+        RefPtr<Gfx::Bitmap const> icon;
         Widget* widget { nullptr };
         bool modified { false };
     };
diff --git a/Userland/Libraries/LibGUI/TextEditor.cpp b/Userland/Libraries/LibGUI/TextEditor.cpp
index 95b61fb2748..43088e7b6bd 100644
--- a/Userland/Libraries/LibGUI/TextEditor.cpp
+++ b/Userland/Libraries/LibGUI/TextEditor.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, networkException <networkexception@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>
@@ -562,12 +562,12 @@ void TextEditor::paint_event(PaintEvent& event)
                 auto unspanned_color = palette().color(is_enabled() ? foreground_role() : Gfx::ColorRole::DisabledText);
                 if (is_displayonly() && is_focused())
                     unspanned_color = palette().color(is_enabled() ? Gfx::ColorRole::SelectionText : Gfx::ColorRole::DisabledText);
-                RefPtr<Gfx::Font> unspanned_font = this->font();
+                RefPtr<Gfx::Font const> unspanned_font = this->font();
 
                 size_t next_column = 0;
                 Gfx::IntRect span_rect = { visual_line_rect.location(), { 0, line_height() } };
 
-                auto draw_text_helper = [&](size_t start, size_t end, RefPtr<Gfx::Font>& font, Gfx::TextAttributes text_attributes) {
+                auto draw_text_helper = [&](size_t start, size_t end, RefPtr<Gfx::Font const>& font, Gfx::TextAttributes text_attributes) {
                     size_t length = end - start;
                     if (length == 0)
                         return;
diff --git a/Userland/Libraries/LibGUI/TextEditor.h b/Userland/Libraries/LibGUI/TextEditor.h
index 9e7b2903815..903dbd90467 100644
--- a/Userland/Libraries/LibGUI/TextEditor.h
+++ b/Userland/Libraries/LibGUI/TextEditor.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>
  *
@@ -438,7 +438,7 @@ private:
 
     Gfx::IntPoint m_last_mousemove_position;
 
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
 
     bool m_text_is_secret { false };
 
diff --git a/Userland/Libraries/LibGUI/Tray.cpp b/Userland/Libraries/LibGUI/Tray.cpp
index dccfc5d223a..d91cc3655d0 100644
--- a/Userland/Libraries/LibGUI/Tray.cpp
+++ b/Userland/Libraries/LibGUI/Tray.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -33,7 +33,7 @@ Gfx::IntRect Tray::Item::rect(Tray const& tray) const
     };
 }
 
-size_t Tray::add_item(DeprecatedString text, RefPtr<Gfx::Bitmap> bitmap, DeprecatedString custom_data)
+size_t Tray::add_item(DeprecatedString text, RefPtr<Gfx::Bitmap const> bitmap, DeprecatedString custom_data)
 {
     auto new_index = m_items.size();
 
diff --git a/Userland/Libraries/LibGUI/Tray.h b/Userland/Libraries/LibGUI/Tray.h
index 239fd4bd2cb..ef0e2eba408 100644
--- a/Userland/Libraries/LibGUI/Tray.h
+++ b/Userland/Libraries/LibGUI/Tray.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -18,7 +18,7 @@ class Tray : public GUI::Frame {
 public:
     virtual ~Tray() override = default;
 
-    size_t add_item(DeprecatedString text, RefPtr<Gfx::Bitmap>, DeprecatedString custom_data);
+    size_t add_item(DeprecatedString text, RefPtr<Gfx::Bitmap const>, DeprecatedString custom_data);
 
     void set_item_checked(size_t index, bool);
 
@@ -39,7 +39,7 @@ private:
 
     struct Item {
         DeprecatedString text;
-        RefPtr<Gfx::Bitmap> bitmap;
+        RefPtr<Gfx::Bitmap const> bitmap;
         DeprecatedString custom_data;
         size_t index { 0 };
         Gfx::IntRect rect(Tray const&) const;
diff --git a/Userland/Libraries/LibGUI/TreeViewModel.h b/Userland/Libraries/LibGUI/TreeViewModel.h
index fcbf143c141..6021fbf519f 100644
--- a/Userland/Libraries/LibGUI/TreeViewModel.h
+++ b/Userland/Libraries/LibGUI/TreeViewModel.h
@@ -49,7 +49,7 @@ public:
         requires(IsBaseOf<Node, NodeType>)
         {
             auto node = adopt_ref(*new NodeType(move(text), move(icon), this, forward<Args>(args)...));
-            m_child_nodes.append(*static_cast<Node const*>(node.ptr()));
+            m_child_nodes.append(*static_cast<Node*>(node.ptr()));
             return node;
         }
 
@@ -77,7 +77,7 @@ public:
     requires(IsBaseOf<Node, NodeType>)
     {
         auto node = adopt_ref(*new NodeType(move(text), move(icon), nullptr, forward<Args>(args)...));
-        m_nodes.append(*static_cast<Node const*>(node.ptr()));
+        m_nodes.append(*static_cast<Node*>(node.ptr()));
         return node;
     }
 
diff --git a/Userland/Libraries/LibGUI/Variant.h b/Userland/Libraries/LibGUI/Variant.h
index 2b4adc15595..7de0dda2676 100644
--- a/Userland/Libraries/LibGUI/Variant.h
+++ b/Userland/Libraries/LibGUI/Variant.h
@@ -21,7 +21,7 @@ namespace Detail {
 struct Boolean {
     bool value;
 };
-using VariantUnderlyingType = AK::Variant<Empty, Boolean, float, i32, i64, u32, u64, DeprecatedString, Color, Gfx::IntPoint, Gfx::IntSize, Gfx::IntRect, Gfx::TextAlignment, Gfx::ColorRole, Gfx::AlignmentRole, Gfx::FlagRole, Gfx::MetricRole, Gfx::PathRole, NonnullRefPtr<Gfx::Bitmap>, NonnullRefPtr<Gfx::Font>, GUI::Icon>;
+using VariantUnderlyingType = AK::Variant<Empty, Boolean, float, i32, i64, u32, u64, DeprecatedString, Color, Gfx::IntPoint, Gfx::IntSize, Gfx::IntRect, Gfx::TextAlignment, Gfx::ColorRole, Gfx::AlignmentRole, Gfx::FlagRole, Gfx::MetricRole, Gfx::PathRole, NonnullRefPtr<Gfx::Bitmap const>, NonnullRefPtr<Gfx::Font const>, GUI::Icon>;
 }
 
 class Variant : public Detail::VariantUnderlyingType {
@@ -57,7 +57,7 @@ public:
 
     template<OneOfIgnoringCV<Gfx::Bitmap, Gfx::Font> T>
     Variant(T const& value)
-        : Variant(NonnullRefPtr<RemoveCV<T>>(value))
+        : Variant(NonnullRefPtr<RemoveCV<T> const>(value))
     {
     }
     template<OneOfIgnoringCV<Gfx::Bitmap, Gfx::Font> T>
@@ -77,13 +77,13 @@ public:
     bool is_u64() const { return has<u64>(); }
     bool is_float() const { return has<float>(); }
     bool is_string() const { return has<DeprecatedString>(); }
-    bool is_bitmap() const { return has<NonnullRefPtr<Gfx::Bitmap>>(); }
+    bool is_bitmap() const { return has<NonnullRefPtr<Gfx::Bitmap const>>(); }
     bool is_color() const { return has<Color>(); }
     bool is_icon() const { return has<GUI::Icon>(); }
     bool is_point() const { return has<Gfx::IntPoint>(); }
     bool is_size() const { return has<Gfx::IntSize>(); }
     bool is_rect() const { return has<Gfx::IntRect>(); }
-    bool is_font() const { return has<NonnullRefPtr<Gfx::Font>>(); }
+    bool is_font() const { return has<NonnullRefPtr<Gfx::Font const>>(); }
     bool is_text_alignment() const { return has<Gfx::TextAlignment>(); }
     bool is_color_role() const { return has<Gfx::ColorRole>(); }
     bool is_alignment_role() const { return has<Gfx::AlignmentRole>(); }
@@ -103,7 +103,7 @@ public:
             [](Gfx::IntPoint const& v) { return !v.is_zero(); },
             [](OneOf<Gfx::IntRect, Gfx::IntSize> auto const& v) { return !v.is_empty(); },
             [](Enum auto const&) { return true; },
-            [](OneOf<float, DeprecatedString, Color, NonnullRefPtr<Gfx::Font>, NonnullRefPtr<Gfx::Bitmap>, GUI::Icon> auto const&) { return true; });
+            [](OneOf<float, DeprecatedString, Color, NonnullRefPtr<Gfx::Font const>, NonnullRefPtr<Gfx::Bitmap const>, GUI::Icon> auto const&) { return true; });
     }
 
     i32 as_i32() const { return get<i32>(); }
@@ -126,7 +126,7 @@ public:
                     return v.to_int<T>().value_or(0);
             },
             [](Enum auto const&) -> T { return 0; },
-            [](OneOf<Gfx::IntPoint, Gfx::IntRect, Gfx::IntSize, Color, NonnullRefPtr<Gfx::Font>, NonnullRefPtr<Gfx::Bitmap>, GUI::Icon> auto const&) -> T { return 0; });
+            [](OneOf<Gfx::IntPoint, Gfx::IntRect, Gfx::IntSize, Color, NonnullRefPtr<Gfx::Font const>, NonnullRefPtr<Gfx::Bitmap const>, GUI::Icon> auto const&) -> T { return 0; });
     }
 
     i32 to_i32() const { return to_integer<i32>(); }
@@ -144,10 +144,10 @@ public:
     Gfx::IntSize as_size() const { return get<Gfx::IntSize>(); }
     Gfx::IntRect as_rect() const { return get<Gfx::IntRect>(); }
     DeprecatedString as_string() const { return get<DeprecatedString>(); }
-    Gfx::Bitmap const& as_bitmap() const { return *get<NonnullRefPtr<Gfx::Bitmap>>(); }
+    Gfx::Bitmap const& as_bitmap() const { return *get<NonnullRefPtr<Gfx::Bitmap const>>(); }
     GUI::Icon as_icon() const { return get<GUI::Icon>(); }
     Color as_color() const { return get<Color>(); }
-    Gfx::Font const& as_font() const { return *get<NonnullRefPtr<Gfx::Font>>(); }
+    Gfx::Font const& as_font() const { return *get<NonnullRefPtr<Gfx::Font const>>(); }
 
     Gfx::TextAlignment to_text_alignment(Gfx::TextAlignment default_value) const
     {
@@ -211,8 +211,8 @@ public:
             [](Gfx::FlagRole v) { return DeprecatedString::formatted("Gfx::FlagRole::{}", Gfx::to_string(v)); },
             [](Gfx::MetricRole v) { return DeprecatedString::formatted("Gfx::MetricRole::{}", Gfx::to_string(v)); },
             [](Gfx::PathRole v) { return DeprecatedString::formatted("Gfx::PathRole::{}", Gfx::to_string(v)); },
-            [](NonnullRefPtr<Gfx::Font> const& font) { return DeprecatedString::formatted("[Font: {}]", font->name()); },
-            [](NonnullRefPtr<Gfx::Bitmap> const&) -> DeprecatedString { return "[Gfx::Bitmap]"; },
+            [](NonnullRefPtr<Gfx::Font const> const& font) { return DeprecatedString::formatted("[Font: {}]", font->name()); },
+            [](NonnullRefPtr<Gfx::Bitmap const> const&) -> DeprecatedString { return "[Gfx::Bitmap]"; },
             [](GUI::Icon const&) -> DeprecatedString { return "[GUI::Icon]"; },
             [](Detail::Boolean v) { return DeprecatedString::formatted("{}", v.value); },
             [](auto const& v) { return DeprecatedString::formatted("{}", v); });
diff --git a/Userland/Libraries/LibGUI/Widget.cpp b/Userland/Libraries/LibGUI/Widget.cpp
index ce16af49ce6..f08a80f0245 100644
--- a/Userland/Libraries/LibGUI/Widget.cpp
+++ b/Userland/Libraries/LibGUI/Widget.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -1042,7 +1042,7 @@ Vector<Widget&> Widget::child_widgets() const
     return widgets;
 }
 
-void Widget::set_palette(Palette const& palette)
+void Widget::set_palette(Palette& palette)
 {
     m_palette = palette.impl();
     update();
@@ -1126,14 +1126,14 @@ Gfx::IntRect Widget::children_clip_rect() const
     return rect();
 }
 
-void Widget::set_override_cursor(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> cursor)
+void Widget::set_override_cursor(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> cursor)
 {
-    auto const& are_cursors_the_same = [](AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const& a, AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const& b) {
-        if (a.has<Gfx::StandardCursor>() != b.has<Gfx::StandardCursor>())
+    auto const& are_cursors_the_same = [](auto const& a, auto const& b) {
+        if (a.template has<Gfx::StandardCursor>() != b.template has<Gfx::StandardCursor>())
             return false;
-        if (a.has<Gfx::StandardCursor>())
-            return a.get<Gfx::StandardCursor>() == b.get<Gfx::StandardCursor>();
-        return a.get<NonnullRefPtr<Gfx::Bitmap>>().ptr() == b.get<NonnullRefPtr<Gfx::Bitmap>>().ptr();
+        if (a.template has<Gfx::StandardCursor>())
+            return a.template get<Gfx::StandardCursor>() == b.template get<Gfx::StandardCursor>();
+        return a.template get<NonnullRefPtr<Gfx::Bitmap const>>().ptr() == b.template get<NonnullRefPtr<Gfx::Bitmap const>>().ptr();
     };
 
     if (are_cursors_the_same(m_override_cursor, cursor))
@@ -1159,19 +1159,19 @@ ErrorOr<void> Widget::load_from_gml(StringView gml_string, UnregisteredChildHand
     return load_from_gml_ast(value, unregistered_child_handler);
 }
 
-ErrorOr<void> Widget::load_from_gml_ast(NonnullRefPtr<GUI::GML::Node> ast, UnregisteredChildHandler unregistered_child_handler)
+ErrorOr<void> Widget::load_from_gml_ast(NonnullRefPtr<GUI::GML::Node const> ast, UnregisteredChildHandler unregistered_child_handler)
 {
     if (is<GUI::GML::GMLFile>(ast.ptr()))
-        return load_from_gml_ast(static_ptr_cast<GUI::GML::GMLFile>(ast)->main_class(), unregistered_child_handler);
+        return load_from_gml_ast(static_cast<GUI::GML::GMLFile const&>(*ast).main_class(), unregistered_child_handler);
 
     VERIFY(is<GUI::GML::Object>(ast.ptr()));
-    auto object = static_ptr_cast<GUI::GML::Object>(ast);
+    auto const& object = static_cast<GUI::GML::Object const&>(*ast);
 
-    object->for_each_property([&](auto key, auto value) {
+    object.for_each_property([&](auto key, auto value) {
         set_property(key, value);
     });
 
-    auto layout = object->layout_object();
+    auto layout = object.layout_object();
     if (!layout.is_null()) {
         auto class_name = layout->name();
         if (class_name.is_null()) {
@@ -1198,8 +1198,8 @@ ErrorOr<void> Widget::load_from_gml_ast(NonnullRefPtr<GUI::GML::Node> ast, Unreg
 
     auto& widget_class = *Core::ObjectClassRegistration::find("GUI::Widget"sv);
     bool is_tab_widget = is<TabWidget>(*this);
-    TRY(object->try_for_each_child_object([&](auto child_data) -> ErrorOr<void> {
-        auto class_name = child_data->name();
+    TRY(object.try_for_each_child_object([&](auto const& child_data) -> ErrorOr<void> {
+        auto class_name = child_data.name();
 
         // It is very questionable if this pseudo object should exist, but it works fine like this for now.
         if (class_name == "GUI::Layout::Spacer") {
diff --git a/Userland/Libraries/LibGUI/Widget.h b/Userland/Libraries/LibGUI/Widget.h
index 75d723467c0..f49eea7db14 100644
--- a/Userland/Libraries/LibGUI/Widget.h
+++ b/Userland/Libraries/LibGUI/Widget.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -332,7 +332,7 @@ public:
     void do_layout();
 
     Gfx::Palette palette() const;
-    void set_palette(Gfx::Palette const&);
+    void set_palette(Gfx::Palette&);
 
     DeprecatedString title() const;
     void set_title(DeprecatedString);
@@ -349,8 +349,8 @@ public:
 
     virtual Gfx::IntRect children_clip_rect() const;
 
-    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const& override_cursor() const { return m_override_cursor; }
-    void set_override_cursor(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>>);
+    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> const& override_cursor() const { return m_override_cursor; }
+    void set_override_cursor(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>>);
 
     using UnregisteredChildHandler = ErrorOr<NonnullRefPtr<Core::Object>>(DeprecatedString const&);
     ErrorOr<void> load_from_gml(StringView);
@@ -363,7 +363,7 @@ public:
     bool has_pending_drop() const;
 
     // In order for others to be able to call this, it needs to be public.
-    virtual ErrorOr<void> load_from_gml_ast(NonnullRefPtr<GUI::GML::Node> ast, UnregisteredChildHandler);
+    virtual ErrorOr<void> load_from_gml_ast(NonnullRefPtr<GUI::GML::Node const> ast, UnregisteredChildHandler);
 
     ErrorOr<void> add_spacer();
 
@@ -439,7 +439,7 @@ private:
     Gfx::IntRect m_relative_rect;
     Gfx::ColorRole m_background_role;
     Gfx::ColorRole m_foreground_role;
-    NonnullRefPtr<Gfx::Font> m_font;
+    NonnullRefPtr<Gfx::Font const> m_font;
     DeprecatedString m_tooltip;
 
     UISize m_min_size { SpecialDimension::Shrink };
@@ -464,7 +464,7 @@ private:
     Vector<WeakPtr<Widget>> m_focus_delegators;
     FocusPolicy m_focus_policy { FocusPolicy::NoFocus };
 
-    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> m_override_cursor { Gfx::StandardCursor::None };
+    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> m_override_cursor { Gfx::StandardCursor::None };
 };
 
 inline Widget* Widget::parent_widget()
diff --git a/Userland/Libraries/LibGUI/Window.cpp b/Userland/Libraries/LibGUI/Window.cpp
index b41686fbc1d..519c6e54eea 100644
--- a/Userland/Libraries/LibGUI/Window.cpp
+++ b/Userland/Libraries/LibGUI/Window.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -336,13 +336,13 @@ void Window::make_window_manager(unsigned event_mask)
     GUI::ConnectionToWindowManagerServer::the().async_set_manager_window(m_window_id);
 }
 
-bool Window::are_cursors_the_same(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const& left, AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const& right) const
+bool Window::are_cursors_the_same(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> const& left, AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> const& right) const
 {
     if (left.has<Gfx::StandardCursor>() != right.has<Gfx::StandardCursor>())
         return false;
     if (left.has<Gfx::StandardCursor>())
         return left.get<Gfx::StandardCursor>() == right.get<Gfx::StandardCursor>();
-    return left.get<NonnullRefPtr<Gfx::Bitmap>>().ptr() == right.get<NonnullRefPtr<Gfx::Bitmap>>().ptr();
+    return left.get<NonnullRefPtr<Gfx::Bitmap const>>().ptr() == right.get<NonnullRefPtr<Gfx::Bitmap const>>().ptr();
 }
 
 void Window::set_cursor(Gfx::StandardCursor cursor)
@@ -353,7 +353,7 @@ void Window::set_cursor(Gfx::StandardCursor cursor)
     update_cursor();
 }
 
-void Window::set_cursor(NonnullRefPtr<Gfx::Bitmap> cursor)
+void Window::set_cursor(NonnullRefPtr<Gfx::Bitmap const> cursor)
 {
     if (are_cursors_the_same(m_cursor, cursor))
         return;
@@ -987,11 +987,12 @@ void Window::set_icon(Gfx::Bitmap const* icon)
 
     Gfx::IntSize icon_size = icon ? icon->size() : Gfx::IntSize(16, 16);
 
-    m_icon = Gfx::Bitmap::create(Gfx::BitmapFormat::BGRA8888, icon_size).release_value_but_fixme_should_propagate_errors();
+    auto new_icon = Gfx::Bitmap::create(Gfx::BitmapFormat::BGRA8888, icon_size).release_value_but_fixme_should_propagate_errors();
     if (icon) {
-        Painter painter(*m_icon);
+        Painter painter(*new_icon);
         painter.blit({ 0, 0 }, *icon, icon->rect());
     }
+    m_icon = move(new_icon);
 
     apply_icon();
 }
@@ -1252,7 +1253,7 @@ void Window::update_cursor()
     auto new_cursor = m_cursor;
 
     auto is_usable_cursor = [](auto& cursor) {
-        return cursor.template has<NonnullRefPtr<Gfx::Bitmap>>() || cursor.template get<Gfx::StandardCursor>() != Gfx::StandardCursor::None;
+        return cursor.template has<NonnullRefPtr<Gfx::Bitmap const>>() || cursor.template get<Gfx::StandardCursor>() != Gfx::StandardCursor::None;
     };
 
     // NOTE: If there's an automatic cursor tracking widget, we retain its cursor until tracking stops.
@@ -1268,8 +1269,8 @@ void Window::update_cursor()
         return;
     m_effective_cursor = new_cursor;
 
-    if (new_cursor.has<NonnullRefPtr<Gfx::Bitmap>>())
-        ConnectionToWindowServer::the().async_set_window_custom_cursor(m_window_id, new_cursor.get<NonnullRefPtr<Gfx::Bitmap>>()->to_shareable_bitmap());
+    if (new_cursor.has<NonnullRefPtr<Gfx::Bitmap const>>())
+        ConnectionToWindowServer::the().async_set_window_custom_cursor(m_window_id, new_cursor.get<NonnullRefPtr<Gfx::Bitmap const>>()->to_shareable_bitmap());
     else
         ConnectionToWindowServer::the().async_set_window_cursor(m_window_id, (u32)new_cursor.get<Gfx::StandardCursor>());
 }
diff --git a/Userland/Libraries/LibGUI/Window.h b/Userland/Libraries/LibGUI/Window.h
index fbf1b552eaa..335f9dd0d17 100644
--- a/Userland/Libraries/LibGUI/Window.h
+++ b/Userland/Libraries/LibGUI/Window.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -183,7 +183,7 @@ public:
     void set_resize_aspect_ratio(Optional<Gfx::IntSize> const& ratio);
 
     void set_cursor(Gfx::StandardCursor);
-    void set_cursor(NonnullRefPtr<Gfx::Bitmap>);
+    void set_cursor(NonnullRefPtr<Gfx::Bitmap const>);
 
     void set_icon(Gfx::Bitmap const*);
     void apply_icon();
@@ -270,7 +270,7 @@ private:
     void flip(Vector<Gfx::IntRect, 32> const& dirty_rects);
     void force_update();
 
-    bool are_cursors_the_same(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const&, AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> const&) const;
+    bool are_cursors_the_same(AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> const&, AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> const&) const;
 
     WeakPtr<Widget> m_previously_focused_widget;
 
@@ -279,7 +279,7 @@ private:
 
     NonnullRefPtr<Menubar> m_menubar;
 
-    RefPtr<Gfx::Bitmap> m_icon;
+    RefPtr<Gfx::Bitmap const> m_icon;
     int m_window_id { 0 };
     float m_opacity_when_windowless { 1.0f };
     float m_alpha_hit_threshold { 0.0f };
@@ -296,8 +296,8 @@ private:
     Gfx::IntSize m_base_size;
     WindowType m_window_type { WindowType::Normal };
     WindowMode m_window_mode { WindowMode::Modeless };
-    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> m_cursor { Gfx::StandardCursor::None };
-    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap>> m_effective_cursor { Gfx::StandardCursor::None };
+    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> m_cursor { Gfx::StandardCursor::None };
+    AK::Variant<Gfx::StandardCursor, NonnullRefPtr<Gfx::Bitmap const>> m_effective_cursor { Gfx::StandardCursor::None };
     bool m_has_alpha_channel { false };
     bool m_double_buffering_enabled { true };
     bool m_resizable { true };