### 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

/
saved_node_pos = p_point + Vector2(0, i * 250 * EDSCALE);
						saved_node_pos_dirty = true;
						_add_node(cubemap_node_option_idx, {}, arr[i], i);
					}
				}
			}
			undo_redo->commit_action();
		}
	}
}
void VisualShaderEditor::_show_preview_text() {
	preview_showed = !preview_showed;
	if (preview_showed) {
		if (preview_first) {
			preview_window->set_size(Size2(400 * EDSCALE, 600 * EDSCALE));
			preview_window->popup_centered();
			preview_first = false;
		} else {
			preview_window->popup();
		}
		_preview_size_changed();
		if (pending_update_preview) {
			_update_preview();
			pending_update_preview = false;
		}
	} else {
		preview_window->hide();
	}
}
void VisualShaderEditor::_preview_close_requested() {