Provide a callback to initialize the edit-games-dialog before it is shown, to avoid the checkbox checking animation.

Still can't be an __init__ argument with the games- we need to add games to an already open window.

lutris/game_actions.py

@@ -159,8 +159,11 @@ class GameActions:
 
     def on_edit_game_categories(self, _widget):
         """Edit game categories"""
-        dlg = self.application.show_window(EditGameCategoriesDialog, parent=self.window)
-        dlg.add_games(self.get_games())
+
+        def add_games(window):
+            window.add_games(self.get_games())
+
+        self.application.show_window(EditGameCategoriesDialog, update_function=add_games, parent=self.window)
 
 
 class MultiGameActions(GameActions):

lutris/gui/application.py

@@ -361,11 +361,12 @@ class Application(Gtk.Application):
             return kwargs["game"].id
         return str(kwargs)
 
-    def show_window(self, window_class, **kwargs):
+    def show_window(self, window_class, /, update_function=None, **kwargs):
         """Instantiate a window keeping 1 instance max
 
         Params:
             window_class (Gtk.Window): class to create the instance from
+            update_function (Callable): Function to initialize or update the window (if possible before being shown)
             kwargs (dict): Additional arguments to pass to the instanciated window
 
         Returns:
@@ -374,7 +375,10 @@ class Application(Gtk.Application):
         window_key = str(window_class.__name__) + self.get_window_key(**kwargs)
         if self.app_windows.get(window_key):
             self.app_windows[window_key].present()
-            return self.app_windows[window_key]
+            window_inst = self.app_windows[window_key]
+            if update_function:
+                update_function(window_inst)
+            return window_inst
         if issubclass(window_class, Gtk.Dialog):
             if "parent" in kwargs:
                 window_inst = window_class(**kwargs)
@@ -384,6 +388,8 @@ class Application(Gtk.Application):
         else:
             window_inst = window_class(application=self, **kwargs)
         window_inst.connect("destroy", self.on_app_window_destroyed, self.get_window_key(**kwargs))
+        if update_function:
+            update_function(window_inst)
         self.app_windows[window_key] = window_inst
         logger.debug("Showing window %s", window_key)
         window_inst.show()

lutris/gui/config/edit_game_categories.py

@@ -31,7 +31,7 @@ class EditGameCategoriesDialog(SavableModelessDialog):
         self.vbox.pack_start(self._create_category_checkboxes(), True, True, 0)
         self.vbox.pack_start(self._create_add_category(), False, False, 0)
 
-        self.show_all()
+        self.vbox.show_all()
 
     def add_games(self, games: Sequence[Game]) -> None:
         def mark_category_checkbox(checkbox, included):