docs: protected void handleDelete() {
      ModifiableDBIDs todel = DBIDUtil.newHashSet();
      ModifiableDBIDs remain = DBIDUtil.newHashSet(dbids);
      DBIDArrayIter it = dbids.iter();
      for(int row : table.getSelectedRows()) {
        it.seek(row);
        todel.add(it);
        remain.remove(it);
      }
      // Unselect first ...
      context.setSelection(new DBIDSelection(remain));
      // Now delete them.
      for(DBIDIter iter = todel.iter(); iter.valid(); iter.advance()) {
        database.delete(iter);
      }
    }