### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Window 11, Forward+, GTX 1060

### Issue description

Adding two theme variations in a row result to a  crash.

https://user-images.githubusercontent.com/93253123/217037249-1ce1d56d-beb6-4435-83ad-9f8a07fe0e96.mp4



### Steps to reproduce

1. Create a project.
2. Create a theme.
3. Double click to go in the theme editor.
4. Click on manage items buttons.
5. In the add type field type a name to add a type.
6. type another name to add a second type.
7. Crash.

### Minimal reproduction project

[ThemeVariationCrash.zip](https://github.com/godotengine/godot/files/10665863/ThemeVariationCrash.zip)

control_dropping->set_visible(vbox->is_visible_in_tree());
}
void EditorInspectorArray::_panel_draw(int p_index) {
	ERR_FAIL_INDEX(p_index, (int)array_elements.size());
	Ref<StyleBox> style = get_theme_stylebox(SNAME("Focus"), SNAME("EditorStyles"));
	if (!style.is_valid()) {
		return;
	}
	if (array_elements[p_index].panel->has_focus()) {
		array_elements[p_index].panel->draw_style_box(style, Rect2(Vector2(), array_elements[p_index].panel->get_size()));
	}
}
void EditorInspectorArray::_panel_gui_input(Ref<InputEvent> p_event, int p_index) {