private void removeDescendants(VirtualFile file, VirtualFilePointerContainer container) {
   for (VirtualFile virtualFile : container.getFiles()) {
     if (VfsUtil.isAncestor(file, virtualFile, false)) {
       container.remove(myPointerManager.create(virtualFile, this, null));
     }
   }
 }
 private static boolean isUnder(VirtualFile file, final VirtualFilePointerContainer container) {
   for (VirtualFile excludedFile : container.getFiles()) {
     if (VfsUtil.isAncestor(excludedFile, file, false)) {
       return true;
     }
   }
   return false;
 }