/**
   * Method eraseSourceFeedback. Show the source drag feedback for the drag occurring within the
   * viewer.
   */
  private void eraseSourceFeedback() {
    if (!isShowingFeedback()) return;
    setShowingFeedback(false);
    List editParts = getOperationSet();

    for (int i = 0; i < editParts.size(); i++) {
      EditPart editPart = (EditPart) editParts.get(i);
      editPart.eraseSourceFeedback(getSourceRequest());
    }
  }