I think I found the problem!

It seems to only exhibit when you dismiss the configuration dialog by using keyboard (pressing Enter in this case).

If you close the dialog by mouse-clicking OK, everything’s working all right. At least that’s what my examination shows.

The problem is actually very interesting and is related to the way Windows handles messages in modeless dialogs (BTW have you ever noticed that the config dialogs are modeless - ie. you can jump in the tree without closing and reopening them?)

I hope this will be fixed asap.

Thanks again for your great help!
Vlk