gtk: make app non-unique

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

qemu-gtk4/src/application.rs

@@ -92,7 +92,7 @@ impl QemuApplication {
     pub fn new() -> Self {
         glib::Object::new(&[
             ("application-id", &Some(config::APP_ID)),
-            ("flags", &ApplicationFlags::empty()),
+            ("flags", &ApplicationFlags::NON_UNIQUE),
         ])
         .expect("Application initialization failed...")
     }

qemu-gtk4/src/console.rs

@@ -192,6 +192,7 @@ impl QemuConsole {
             }),
         );
         priv_.console.set(console).unwrap();
+        priv_.area.grab_focus();
     }
 
     fn qemu_console(&self) -> &Console {