public boolean isValid() {
    if (myModules != null){
      for (Module module : myModules) {
        if (module.isDisposed()) return false;
      }
      return true;
    }
    if (myModule != null) return !myModule.isDisposed();
    if (myElement != null) {
      return myElement.isValid();
    }
    return myType == VIRTUAL_FILES || myType == CUSTOM || myType == PROJECT;
  }
public boolean isValid()