Merge pull request #112297 from UrbanHelix/borderless-border-bug

[Windows] Fix legacy border when toggling borderless while fullscreen

Author: Repiteo

platform/windows/display_server_windows.cpp

@@ -2623,6 +2623,9 @@ void DisplayServerWindows::window_set_flag(WindowFlags p_flag, bool p_enabled, W
 		} break;
 		case WINDOW_FLAG_BORDERLESS: {
 			wd.borderless = p_enabled;
+			if (wd.fullscreen) {
+				return;
+			}
 			_update_window_mouse_passthrough(p_window);
 			_update_window_style(p_window);
 			ShowWindow(wd.hWnd, (wd.no_focus || wd.is_popup) ? SW_SHOWNOACTIVATE : SW_SHOW); // Show the window.