Added some clean up in camera/viewport management. Fixes #12279, Fixes #12774

scene/3d/camera.cpp

@@ -191,11 +191,12 @@ void Camera::_update_camera() {
 		get_viewport()->_camera_transform_changed_notify();
 	*/
 
-	if (is_inside_tree() && is_current()) {
-		get_viewport()->_camera_transform_changed_notify();
-	}
+	if (!is_inside_tree() || get_tree()->is_node_being_edited(this) || !is_current())
+		return;
+
+	get_viewport()->_camera_transform_changed_notify();
 
-	if (is_current() && get_world().is_valid()) {
+	if (get_world().is_valid()) {
 		get_world()->_update_camera(this);
 	}
 }

scene/main/viewport.cpp

@@ -936,6 +936,9 @@ void Viewport::_camera_remove(Camera *p_camera) {
 
 	cameras.erase(p_camera);
 	if (camera == p_camera) {
+		if (camera && find_world().is_valid()) {
+			camera->notification(Camera::NOTIFICATION_LOST_CURRENT);
+		}
 		camera = NULL;
 	}
 }