>>Happens even with the location where the click actually happened (the first hittest check before the loop).
>>
>>I wonder whether this has anything to do with the version of Treeview. Digging back through UT messages, I found my own message from late nineties where I have found some differences in behavior between MSComctlLib.TreeCtrl.2 and COMCTL.TreeCtrl.1 - and I have never had problems with the latter. It also calls .hittest() and, after checking it, yes it still works OK. And the problematic class uses the MSComctlLib.TreeCtrl.2, of course.
>
>I tested with MSComctlLib.TreeCtrl.2 and couldn't brake it.

And I tested some more with the one we have and it breaks all over the place. Maybe it just needs to be reinstalled - who knows what's up. Weird indeed.