fix: single instance flutter in linux?

linux/my_application.cc

@@ -48,6 +48,7 @@ static void my_application_activate(GApplication *application)
     gtk_header_bar_set_title(header_bar, "Hiddify");
     gtk_header_bar_set_show_close_button(header_bar, TRUE);
     gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
+    
   }
   else
   {
@@ -67,6 +68,7 @@ static void my_application_activate(GApplication *application)
   fl_register_plugins(FL_PLUGIN_REGISTRY(view));
 
   gtk_widget_grab_focus(GTK_WIDGET(view));
+  
 }
 
 // Implements GApplication::local_command_line.
@@ -133,6 +135,6 @@ MyApplication *my_application_new()
 {
   return MY_APPLICATION(g_object_new(my_application_get_type(),
                                      "application-id", APPLICATION_ID,
-                                     "flags", G_APPLICATION_NON_UNIQUE,
+                                     "flags", G_APPLICATION_FLAGS_NONE,
                                      nullptr));
 }