Use 'return -code error ...' instead of 'error ...'

[flopp]

xdnd::GetDroppedData uses error to report back an exceptional situation: there's no common DND data type; this situation also occurs when dragging some object over a non-DND-aware widget within a Tk application => this error statement is called often in a normal application.

xdnd::GetDroppedData is used via xdnd::GetPositionData in a catch block within xdnd::HandleXdndPosition.

If your application uses a custom error handler by redefining error, those error calls end up in the custom error handler, although these are not really error situations, but normal behaviour.

=> It would be better to use return -code error ... in this case.