GUI2/Listbox: added select_last_row wrapper

src/gui/dialogs/campaign_difficulty.cpp

@@ -143,7 +143,7 @@ void campaign_difficulty::pre_show(window& window)
 		grid& grid = list.add_row(data);
 
 		if(d["default"].to_bool(false)) {
-			list.select_row(list.get_item_count() - 1);
+			list.select_last_row();
 		}
 
 		widget* widget = grid.find("victory", false);

src/gui/dialogs/editor/generate_map.cpp

@@ -123,7 +123,7 @@ void editor_generate_map::pre_show(window& window)
 		list.add_row(lrow);
 
 		if(gen.get() == last_map_generator_) {
-			list.select_row(list.get_item_count() - 1);
+			list.select_last_row();
 		}
 	}
 

src/gui/dialogs/file_dialog.cpp

@@ -540,7 +540,6 @@ void file_dialog::push_fileview_row(listbox& filelist, const std::string& name,
 	data["file"]["label"] = label;
 
 	grid& last_grid = filelist.add_row(data);
-	const unsigned last_pos = filelist.get_item_count() - 1;
 
 	//
 	// Crummy hack around the lack of an option to hook into row double click
@@ -551,7 +550,7 @@ void file_dialog::push_fileview_row(listbox& filelist, const std::string& name,
 			.set_retval(FILE_DIALOG_ITEM_RETVAL);
 
 	if(check_selection && name == current_entry_) {
-		filelist.select_row(last_pos, true);
+		filelist.select_last_row(true);
 	}
 }
 

src/gui/dialogs/language_selection.cpp

@@ -75,7 +75,7 @@ void language_selection::pre_show(window& window)
 
 		list.add_row(data);
 		if(lang == current_language) {
-			list.select_row(list.get_item_count() - 1);
+			list.select_last_row();
 		}
 	}
 }

src/gui/dialogs/unit_create.cpp

@@ -142,7 +142,7 @@ void unit_create::pre_show(window& window)
 
 		// Select the previous choice, if any.
 		if(choice_.empty() != true && choice_ == i.first) {
-			list.select_row(list.get_item_count() - 1);
+			list.select_last_row();
 		}
 	}
 

src/gui/widgets/listbox.hpp

@@ -186,6 +186,16 @@ public:
 	 */
 	bool select_row(const unsigned row, const bool select = true);
 
+	/**
+	 * Does exactly as advertised: selects the list's last row.
+	 * 
+	 * @param select              Select or deselect the row.
+	 */
+	bool select_last_row(const bool select = true)
+	{
+		return select_row(get_item_count() - 1, select);
+	}
+
 	/**
 	 * Selects a row at the given position, regardless of sorting order.
 	 *