### 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_theme_item_dialog->add_child(edit_theme_item_vb);
	edit_theme_item_old_vb = memnew(VBoxContainer);
	edit_theme_item_vb->add_child(edit_theme_item_old_vb);
	Label *edit_theme_item_old = memnew(Label);
	edit_theme_item_old->set_text(TTR("Old Name:"));
	edit_theme_item_old_vb->add_child(edit_theme_item_old);
	theme_item_old_name = memnew(Label);
	edit_theme_item_old_vb->add_child(theme_item_old_name);
	Label *edit_theme_item_label = memnew(Label);
	edit_theme_item_label->set_text(TTR("Name:"));
	edit_theme_item_vb->add_child(edit_theme_item_label);
	theme_item_name = memnew(LineEdit);
	edit_theme_item_vb->add_child(theme_item_name);
	theme_item_name->connect("gui_input", callable_mp(this, &ThemeItemEditorDialog::_edit_theme_item_gui_input));
	edit_theme_item_dialog->connect("confirmed", callable_mp(this, &ThemeItemEditorDialog::_confirm_edit_theme_item));
	
	TabContainer *import_tc = memnew(TabContainer);
	import_tc->set_tab_alignment(TabBar::ALIGNMENT_CENTER);
	tc->add_child(import_tc);
	tc->set_tab_title(1, TTR("Import Items"));
	import_default_theme_items = memnew(ThemeItemImportTree);
	import_tc->add_child(import_default_theme_items);
	import_tc->set_tab_title(0, TTR("Default Theme"));
	import_default_theme_items->connect("items_imported", callable_mp(this, &ThemeItemEditorDialog::_update_edit_types));
	import_editor_theme_items = memnew(ThemeItemImportTree);
	import_tc->add_child(import_editor_theme_items);
	import_tc->set_tab_title(1, TTR("Editor Theme"));
	import_editor_theme_items->connect("items_imported", callable_mp(this, &ThemeItemEditorDialog::_update_edit_types));
	VBoxContainer *import_another_theme_vb = memnew(VBoxContainer);
	HBoxContainer *import_another_file_hb = memnew(HBoxContainer);