Moved the easy close behaviour to the window.

At some places click dismiss is used which will be the new name of the
feature since it's a more fitting name.

data/gui/default/widget/window_default.cfg

@@ -98,6 +98,37 @@
 
 		[/foreground]
 
+		[grid]
+
+			[row]
+
+				[column]
+
+					[grid]
+						id = "_content_grid"
+					[/grid]
+
+				[/column]
+
+			[/row]
+
+			[row]
+
+				[column]
+
+					[button]
+						id = "click_dismiss"
+						definition = "default"
+
+						label = "Close"
+					[/button]
+
+				[/column]
+
+			[/row]
+
+		[/grid]
+
 	[/resolution]
 
 [/window_definition]

src/gui/dialogs/message.cpp

@@ -100,20 +100,6 @@ void tmessage::pre_show(CVideo& /*video*/, twindow& window)
 
 	// Override the user value, to make sure it's set properly.
 	window.set_easy_close(auto_close_);
-	if(auto_close_) {
-		/*
-		 * Hide the buttton and do the layout, if window.does_easy_close() is
-		 * false the scroll_label has a scrollbar so we need to show the
-		 * button. When the button is hidden the text for the label is bigger
-		 * and thus not need a scrollbar. Also when the button is visible
-		 * easy_close will always return false.
-		 */
-		window.layout();
-
-		if(window.disable_easy_close()) {
-			set_button_visible(ok, twidget::VISIBLE);
-		}
-	}
 }
 
 void tmessage::post_show(twindow& /*window*/)

src/gui/dialogs/wml_message.cpp

@@ -196,25 +196,7 @@ void twml_message_::pre_show(CVideo& /*video*/, twindow& window)
 	} else {
 		options->set_visible(twidget::INVISIBLE);
 	}
-
-	if(!has_input_) {
-		/*
-		 * Hide the buttton and do the layout, if window.does_easy_close() is
-		 * false the scroll_label has a scrollbar so we need to show the
-		 * button. When the button is hidden the text for the label is bigger
-		 * and thus not need a scrollbar. Also when the button is visible
-		 * easy_close will always return false.
-		 */
-		tbutton* button =
-			dynamic_cast<tbutton*>(window.find_widget("ok", false));
-		VALIDATE(button, missing_widget("ok"));
-		button->set_visible(twidget::INVISIBLE);
-		window.layout();
-
-		if(window.disable_easy_close()) {
-			button->set_visible(twidget::VISIBLE);
-		}
-	}
+	window.set_easy_close(!has_input_ && option_list_.empty());
 }
 
 void twml_message_::post_show(twindow& window)

src/gui/widgets/window.cpp

@@ -28,6 +28,7 @@
 #include "log.hpp"
 #include "gui/auxiliary/log.hpp"
 #include "gui/auxiliary/layout_exception.hpp"
+#include "gui/widgets/button.hpp"
 #ifdef DEBUG_WINDOW_LAYOUT_GRAPHS
 #include "gui/widgets/debug.hpp"
 #endif
@@ -662,7 +663,7 @@ void twindow::remove_linked_widget(const std::string& id
 
 void twindow::layout()
 {
-	/**** Initialize and get initial size. *****/
+	/***** Initialize. *****/
 
 	boost::intrusive_ptr<const twindow_definition::tresolution> conf =
 		boost::dynamic_pointer_cast<const twindow_definition::tresolution>
@@ -671,9 +672,6 @@ void twindow::layout()
 
 	log_scope2(log_gui_layout, "Window: Recalculate size");
 
-	layout_init(true);
-	generate_dot_file("layout_init", LAYOUT);
-
 	const game_logic::map_formula_callable variables =
 		get_screen_size_variables();
 
@@ -689,6 +687,27 @@ void twindow::layout()
 				: settings::screen_height
 			: h_(variables);
 
+	/***** Handle click dismiss status. *****/
+	tbutton* click_dismiss_button = NULL;
+	if((click_dismiss_button
+			= NEW_find_widget<tbutton>(this, "click_dismiss", false, false))) {
+
+		click_dismiss_button->set_visible(twidget::INVISIBLE);
+	}
+	if(easy_close_) {
+		tbutton* button = NEW_find_widget<tbutton>(this, "ok", false, false);
+		if(button) {
+			button->set_visible(twidget::INVISIBLE);
+			click_dismiss_button = button;
+		}
+		VALIDATE(click_dismiss_button
+				, _("Click dismiss needs a 'click_dismiss' or 'ok' button."));
+	}
+
+	/***** Layout. *****/
+	layout_init(true);
+	generate_dot_file("layout_init", LAYOUT);
+
 	layout_linked_widgets();
 
 	try {
@@ -711,12 +730,45 @@ void twindow::layout()
 				"which doesn't fit on the screen."), sstr.str());
 	}
 
+	/****** Validate click dismiss status. *****/
+	if(easy_close_ && disable_easy_close()) {
+		assert(click_dismiss_button);
+		click_dismiss_button->set_visible(twidget::VISIBLE);
+
+
+		layout_init(true);
+		generate_dot_file("layout_init", LAYOUT);
+
+		layout_linked_widgets();
+
+		try {
+			twindow_implementation::layout(
+					*this, maximum_width, maximum_height);
+
+		} catch(tlayout_exception_resize_failed&) {
+
+			/** @todo implement the scrollbars on the window. */
+
+			std::stringstream sstr;
+			sstr << __FILE__ << ":" << __LINE__ << " in function '" << __func__
+				<< "' found the following problem: Failed to size window;"
+				<< " wanted size " << get_best_size()
+				<< " available size "
+				<< maximum_width << ',' << maximum_height
+				<< " screen size "
+				<< settings::screen_width << ',' << settings::screen_height
+				<< '.';
+
+			throw twml_exception(_("Failed to show a dialog, "
+						"which doesn't fit on the screen."), sstr.str());
+		}
+	}
+
+	/***** Get the best location for the window *****/
 	tpoint size = get_best_size();
 
 	assert(size.x <= maximum_width && size.y <= maximum_height);
 
-	/***** Get the best location for the window *****/
-
 	tpoint origin(0, 0);
 
 	if(automatic_placement_) {

src/gui/widgets/window.hpp

@@ -453,6 +453,15 @@ private:
 	 * be closed. The widgets in the window may override this behaviour by
 	 * registering themselves as blockers. This is tested by the function
 	 * disable_easy_close().
+	 *
+	 * The handling of easy close is done in the window, in order to do so a
+	 * window either needs a click_dismiss or an ok button. Both will be hidden
+	 * when not needed and when needed first the ok is tried and then the
+	 * click_dismiss button. this allows adding a click_dismiss button to the
+	 * window definition and use the ok from the window instance.
+	 *
+	 * @todo After testing the click dismiss feature it should be documented in
+	 * the wiki.
 	 */
 	bool easy_close_;