@RequiresEdt
  private @NotNull ShelfToolWindowPanel initToolWindowPanel() {
    if (myPanel == null) {
      Activity activity = StartUpMeasurer.startActivity("ShelvedChangesViewManager initialization");
      myPanel = new ShelfToolWindowPanel(myProject);
      Disposer.register(myPanel, () -> {
        // Content is removed from TW
        myPanel = null;
      });
      updateTreeModel();
      activity.end();
    }
    return myPanel;
  }
@RequiresEdt
  private @NotNull ShelfToolWindowPanel initToolWindowPanel()