Desktop: Focus app window when loading a document (#4124)

editor/src/messages/app_window/app_window_message.rs

@@ -11,6 +11,7 @@ pub enum AppWindowMessage {
 	Maximize,
 	Fullscreen,
 	Drag,
+	Focus,
 	Hide,
 	HideOthers,
 	ShowAll,

editor/src/messages/app_window/app_window_message_handler.rs

@@ -36,6 +36,10 @@ impl MessageHandler<AppWindowMessage, ()> for AppWindowMessageHandler {
 				#[cfg(not(target_family = "wasm"))]
 				responses.add(FrontendMessage::WindowDrag);
 			}
+			AppWindowMessage::Focus => {
+				#[cfg(not(target_family = "wasm"))]
+				responses.add(FrontendMessage::WindowFocus);
+			}
 			AppWindowMessage::Hide => {
 				#[cfg(not(target_family = "wasm"))]
 				responses.add(FrontendMessage::WindowHide);