private boolean createABond(Atom a1, Atom a2) {
		boolean success = createBond(a1, a2);
		if (success) {
			if (!doNotFireUndoEvent) {
				model.getUndoManager().undoableEditHappened(new UndoableEditEvent(model, new UndoableInsertion(DGBD_ID)));
				updateUndoUIComponents();
			}
		}
		return success;
	}