>>>In the Visual Extend framework, there is a certain form, used with a "File | Open" command, to show a list of available forms.
>>>
>>>This form contains a PageFrame and a ListBox. The ListBox is in front of the PageFrame, but it is an independent object (not on any of the pages) - the idea being that its contents are re-loaded depending on the Page selected by the user. (This allows the programmer to divide the forms into categories.)
>>>
>>>The queer part is that on some computers, the ListBox sometimes appears outside the form - as if it where an independent object. With the Did anyone ever see a similar behavior? Would this depend on the version of VFP; on the OS version; or on something else?
>>>
>>>When I tried this today, giving a software demonstration (arrrg...), the first time there was no problem; but after closing and re-opening the "File | Open" form, the problem appeared. After closing and re-opening the EXE, the same pattern. No problem on first open, only later.
>>
>>It sounds like the form was not actually released. Can you verify if it was indeed released?
>
>That assumption sounds very reasonable, considering that the problem only appears on the second opening.
>
>However, how do I go about verifying this?

If the form uses private DS, then not released DS is the identifier of the problem. Otherwise you may try to loop through _screen.forms collection.