Hi Marc,
>Moving the invisible container to another position (like -100,-100)
>was my old solution (that works!). But I ask on UT for someone knowing
>the bug to get a best solution.

It has nothing to do with containers. I ran into the same issue last week. If you overlap two listboxes, visible or not, enabled or not, the click event is not handled properly. I had to resize the underlying listbox so that there was no overlap to get it to work. I haven't installed VFP7 yet to see if that was resolved.