### 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_hsplit->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	left_l_vsplit = memnew(VSplitContainer);
	left_l_hsplit->add_child(left_l_vsplit);
	dock_slot[DOCK_SLOT_LEFT_UL] = memnew(TabContainer);
	left_l_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_UL]);
	dock_slot[DOCK_SLOT_LEFT_BL] = memnew(TabContainer);
	left_l_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_BL]);
	left_r_hsplit = memnew(HSplitContainer);
	left_l_hsplit->add_child(left_r_hsplit);
	left_r_vsplit = memnew(VSplitContainer);
	left_r_hsplit->add_child(left_r_vsplit);
	dock_slot[DOCK_SLOT_LEFT_UR] = memnew(TabContainer);
	left_r_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_UR]);
	dock_slot[DOCK_SLOT_LEFT_BR] = memnew(TabContainer);
	left_r_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_BR]);
	main_hsplit = memnew(HSplitContainer);
	left_r_hsplit->add_child(main_hsplit);
	VBoxContainer *center_vb = memnew(VBoxContainer);
	main_hsplit->add_child(center_vb);
	center_vb->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	center_split = memnew(VSplitContainer);
	center_split->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	center_split->set_collapsed(false);
	center_vb->add_child(center_split);
	right_hsplit = memnew(HSplitContainer);
	main_hsplit->add_child(right_hsplit);
	right_l_vsplit = memnew(VSplitContainer);
	right_hsplit->add_child(right_l_vsplit);
	dock_slot[DOCK_SLOT_RIGHT_UL] = memnew(TabContainer);
	right_l_vsplit->add_child(dock_slot[DOCK_SLOT_RIGHT_UL]);