### Godot version

4.0.dev(2fdaf2919c03ab50f971f2d51616d4ee329d29af)

### System information

any

### Issue description

AnimationPlayer is unintentionally hidden.

https://user-images.githubusercontent.com/61938263/217088704-c1ad44d6-ef7b-4b10-b351-f9f9fa166e39.mp4


### Steps to reproduce

Select AnimationTree -> Select AnimationPlayer

### Minimal reproduction project

N/A
left_l_vsplit->hide();
	right_r_vsplit->hide();
	
	left_r_hsplit->set_split_offset(270 * EDSCALE);
	main_hsplit->set_split_offset(-270 * EDSCALE);
	
	const String docks_section = "docks";
	default_layout.instantiate();
	
	default_layout->set_value(docks_section, "dock_3", "Scene,Import");
	default_layout->set_value(docks_section, "dock_4", "FileSystem");
	default_layout->set_value(docks_section, "dock_5", "Inspector,Node,History");
	for (int i = 0; i < vsplits.size(); i++) {
		default_layout->set_value(docks_section, "dock_split_" + itos(i + 1), 0);
	}
	default_layout->set_value(docks_section, "dock_hsplit_1", 0);
	default_layout->set_value(docks_section, "dock_hsplit_2", 270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_3", -270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_4", 0);
	_update_layouts_menu();
	
	bottom_panel = memnew(PanelContainer);
	bottom_panel->add_theme_style_override("panel", gui_base->get_theme_stylebox(SNAME("BottomPanel"), SNAME("EditorStyles")));
	center_split->add_child(bottom_panel);
	center_split->set_dragger_visibility(SplitContainer::DRAGGER_HIDDEN);
	bottom_panel_vb = memnew(VBoxContainer);
	bottom_panel->add_child(bottom_panel_vb);
	bottom_panel_hb = memnew(HBoxContainer);
	bottom_panel_hb->set_custom_minimum_size(Size2(0, 24 * EDSCALE)); 
	bottom_panel_vb->add_child(bottom_panel_hb);