Could it be listbox's position? Did you try to remove it from the page, make sure no objects are there or overlapping, putting it back and setting its ZOrder property to be in front?

>I have a strange bug that I can't figure out.
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>In my form, I have a set of tabbed pages. On one of the pages I have several listboxes. Almost all of the listboxes trigger the InteractiveChange event when I select an item from their lists. But one listbox does not. I have set a breakpoint on the InteractiveChange method, and it doesn't get hit when I click on an item on the list. The listbox enable property is set to .T.
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>The odd thing: If I click on a tab of one other page in the set, and then return to the page that has the problem listbox, the listbox begins working, and will continue to work as long as that form is running.
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>Clicking on that other page alone is the only thing that I have found that causes the problem listbox to work. Clicking on no other tabs, or other controls makes the problem listbox begin working.
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>So, what is it about the other page that fixes the listbox? I don't know. I have tried putting RETURN statements in the Activate and Init methods of that page, but it still fixes the problem listbox.
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>I would appreciate any suggestions on how to debug this problem.
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>Thanks,
>Jim