As I stated, the combobox is pretty simple:
- the style setting is that for a dropdown list
- it is not bound to a table nor array
- it is populated with AddListItem() (typically in the INIT() of the form)

One thing that I'd not ruled out yet is the possibility of an older VFP runtime library -- we'd run into this before. In this particular case I vaguely recall we did transmit an updated library install -- though the system might've been locked down (with the particular user not having admin privileges) and the install might've silently failed.

>This problem is fully described in an other forum: https://social.msdn.microsoft.com/Forums/en-US/8702a050-8a09-4eaf-8b58-2e6a572512a8/vfp-90-combo-box-select-list-problem?forum=visualfoxprogeneral
>
>>Hi Naoto, I found a bug that may be the one you bumped into or not!
>>
>>On our VFP app here, we have this lasting bug: "when you select from a VFP combo with you pointing device (ie mouse!), it works... Except for the alas common case when the user mouse has, even very shortly, got out of the "dropped-down" part of the list".
>>
>>That's an old one! Possibly corrected by Chen. If that's the case, I'd be glad to know!
>>
>>Difficult to say it in a different way. But this is clearly a very subtle bug. You need to select straight from the list. Any lateral move with your mouse off the dropped-down list will result in a "miss": the change will not be made.
>>
>>Most users do not get into it, since they use their mouse in a "straight way". Others with a sort of a "jittering mouse hand" will discover this bug and learn to "monitor their mouse position on the combobox" more accurately.
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>>I have found no correction to it except to teach the users in the way to use this touchy vfp combo. That's what training sessions are for! But I'd happily follow on this thread if a solution is available!
>>
>>Daniel
>
>The mouse pointer was indeed over the listbox when the user clicked on the item. Thinking back at the situation, I've a vague recollection that I didn't observe the normal "tracking" behavior (where the selection within the listbox would "follow" the mouse pointer -- i.e. the highlighted item in the listbox would "follow" the mouse pointer)