@Override
  public boolean canSelect(PsiFileSystemItem file) {
    VirtualFile vFile = PsiUtilCore.getVirtualFile(file);
    vFile = vFile == null ? null : BackedVirtualFile.getOriginFileIfBacked(vFile);
    if (vFile == null || !vFile.isValid()) return false;

    ProjectFileIndex fileIndex = ProjectRootManager.getInstance(myProject).getFileIndex();
    return fileIndex.isInSourceContent(vFile) ||
           isInLibraryContentOnly(vFile);
  }
@Override
  public boolean canSelect(PsiFileSystemItem file)