### Godot version

4.1 dev2, 4.0.3

### System information

Windows 10, ryzen 5900x, radeon 6950xt (driver: 23.2.2)

### Issue description

There are two bugs:
- When I create a new node, it is created outside of the viewport. (as in first video)
- When I run the project, all the content inside the viewport dont appear. (as in second video)
I believe the second issue is related to the first.

Note: these problems are in RTL editors.

https://github.com/godotengine/godot/assets/121864036/84f0d434-0d1b-4c23-9fb0-510257e2e191


https://github.com/godotengine/godot/assets/121864036/b2bc20c7-1e2e-4d04-99e7-d66860ffced2




### Steps to reproduce

Videos explain.

### Minimal reproduction project

N/A
ERR_MAIN_THREAD_GUARD;
	switch (p_notification) {
		case NOTIFICATION_POSTINITIALIZE: {
			data.initialized = true;
			_invalidate_theme_cache();
			_update_theme_item_cache();
		} break;
		case NOTIFICATION_PARENTED: {
			Node *parent_node = get_parent();
			data.parent_control = Object::cast_to<Control>(parent_node);
			data.parent_window = Object::cast_to<Window>(parent_node);
			data.theme_owner->assign_theme_on_parented(this);
			_update_layout_mode();
		} break;
		case NOTIFICATION_UNPARENTED: {
			data.parent_control = nullptr;
			data.parent_window = nullptr;
			data.theme_owner->clear_theme_on_unparented(this);
		} break;
		case NOTIFICATION_ENTER_TREE: {
#ifdef TOOLS_ENABLED
			if (is_part_of_edited_scene()) {
				
				set_message_translation(false);
				notification(NOTIFICATION_TRANSLATION_CHANGED);
			}
#endif
			notification(NOTIFICATION_THEME_CHANGED);
		} break;
		case NOTIFICATION_POST_ENTER_TREE: {