I think you're missing the problem. If you move your mouse outside of the bounds of the slide control, the control's value still changes when moving the mouse up and down, however, the event is not seen. So you've got a change in the front panel control that's not seen by the event handler.
For consistency, if you wanted to abort the action on the control by moving the mouse out of the bounds of the slide, the slide control would revert to the value prior to the action. Since this doesn't happen, you'll have to either keep your mouse within the control. Setting the event to trigger on Value Change probably won't work since you'll have an event for each incremental change in the slide. Tim
