@Nullable
  private VirtualFilePointer getSelectedFilePointer() {
    TreePath path = myTree.getSelectionPath();
    if (path == null) return null;
    AbstractTreeNode treeNode = (AbstractTreeNode)path.getLastPathComponent();
    return treeNode instanceof FileTreeNode ? ((FileTreeNode)treeNode).getFilePointer() : null;
  }
@Nullable
  private VirtualFilePointer getSelectedFilePointer()