### Godot version

v4.2.beta2.official [f8818f85e]

### System information

Windows 10, 64bit

### Issue description

Some times can't add node in visualshader editor

### Steps to reproduce

1. Open a VisualShader file for edit.
2. Click the `Add Node...` button, it will popup menu, it is OK.
3. Direct close the menu.
4. Clikd the `Add Node...` again, the menu can't popup.
![GIF](https://github.com/godotengine/godot/assets/35988767/1326c63e-3e05-4423-9ec7-7ce305b3f4f5)

### Minimal reproduction project

/
changed = true;
		} else {
			if (visual_shader.ptr() != p_visual_shader) {
				changed = true;
			}
		}
		visual_shader = Ref<VisualShader>(p_visual_shader);
		graph_plugin->register_shader(visual_shader.ptr());
		visual_shader->connect_changed(callable_mp(this, &VisualShaderEditor::_update_preview));
		visual_shader->set_graph_offset(graph->get_scroll_offset() / EDSCALE);
		_set_mode(visual_shader->get_mode());
		_update_nodes();
	} else {
		if (visual_shader.is_valid()) {
			visual_shader->disconnect_changed(callable_mp(this, &VisualShaderEditor::_update_preview));
		}
		visual_shader.unref();
	}
	if (visual_shader.is_null()) {
		hide();
	} else {
		if (changed) { 
			_update_varying_tree();
			_update_options_menu();
			_update_preview();
			_update_graph();
		}
	}
}
void VisualShaderEditor::add_plugin(const Ref<VisualShaderNodePlugin> &p_plugin) {