// tries to remove object from diagram with Undo
public bool Destroy(IRemoveable o)
{
bool res = o.Destroy();
if (res)
{
Undo.Push(new RemoveOperation(o), false);
}
return(res);
}
public override void Do()
{
obj.Destroy();
}
// tries to remove object from diagram with Undo
public bool Destroy( IRemoveable o )
{
bool res = o.Destroy();
if( res )
Undo.Push( new RemoveOperation( o ), false );
return res;
}