Filed validator no error message using swimlanes

[Dennis_H]

I set a field validator and set a display message when the field is blank to not allow the transition and display a message. If you are in the issue and select the next stage the message pops up as expected. If you are on the board and drag the issue to the next stage there is no message but after a few seconds the issue does get moved back to the stage it came from. Is there a setting I'm missing or is this a bug?