### Godot version

4.1.1

### System information

linux

### Issue description

[simplescreenrecorder-2023-08-30_15.01.51.webm](https://github.com/godotengine/godot-proposals/assets/71937306/537d92b9-4f98-4fe6-adf4-71297be0471a)

I guess this wasn't the case before since I could save a layout named "2 monitors".

### Steps to reproduce

press space

### Minimal reproduction project

none
edit_items_add_font->set_disabled(true);
	edit_items_toolbar->add_child(edit_items_add_font);
	edit_items_add_font->connect("pressed", callable_mp(this, &ThemeItemEditorDialog::_open_add_theme_item_dialog).bind(Theme::DATA_TYPE_FONT));
	edit_items_add_font_size = memnew(Button);
	edit_items_add_font_size->set_tooltip_text(TTR("Add Font Size Item"));
	edit_items_add_font_size->set_flat(true);
	edit_items_add_font_size->set_disabled(true);
	edit_items_toolbar->add_child(edit_items_add_font_size);
	edit_items_add_font_size->connect("pressed", callable_mp(this, &ThemeItemEditorDialog::_open_add_theme_item_dialog).bind(Theme::DATA_TYPE_FONT_SIZE));
	edit_items_add_icon = memnew(Button);
	edit_items_add_icon->set_tooltip_text(TTR("Add Icon Item"));
	edit_items_add_icon->set_flat(true);
	edit_items_add_icon->set_disabled(true);
	edit_items_toolbar->add_child(edit_items_add_icon);
	edit_items_add_icon->connect("pressed", callable_mp(this, &ThemeItemEditorDialog::_open_add_theme_item_dialog).bind(Theme::DATA_TYPE_ICON));
	edit_items_add_stylebox = memnew(Button);
	edit_items_add_stylebox->set_tooltip_text(TTR("Add StyleBox Item"));
	edit_items_add_stylebox->set_flat(true);
	edit_items_add_stylebox->set_disabled(true);
	edit_items_toolbar->add_child(edit_items_add_stylebox);
	edit_items_add_stylebox->connect("pressed", callable_mp(this, &ThemeItemEditorDialog::_open_add_theme_item_dialog).bind(Theme::DATA_TYPE_STYLEBOX));
	edit_items_toolbar->add_child(memnew(VSeparator));
	Label *edit_items_toolbar_remove_label = memnew(Label);
	edit_items_toolbar_remove_label->set_text(TTR("Remove Items:"));
	edit_items_toolbar->add_child(edit_items_toolbar_remove_label);
	edit_items_remove_class = memnew(Button);
	edit_items_remove_class->set_tooltip_text(TTR("Remove Class Items"));
	edit_items_remove_class->set_flat(true);
	edit_items_remove_class->set_disabled(true);
	edit_items_toolbar->add_child(edit_items_remove_class);