Mouse wheel over listboxes in VirtualBox GUI makes them empty

[Konstantin Vlasov]

1. Open the Settings dialog for any powered off VM, General page, Basic tab (opened by default).
2. Place mouse cursor over the "Type" drop-down listbox.
3. Scroll the mouse wheel up or down.

Result: The "Type" value is changed correctly, but the "Version" listbox becomes consisting of all the empty lines instead of correct OS versions.

Similar problems can also be reproduced with some other listboxes. Some more examples:

• Port number of a SATA-attached storage (when changed by scroll wheel, the listbox becomes totally empty).
• System -> Motherboard -> Chipset: when scrolling it with mouse wheel, the value is changed correctly, but "Invalid settings detected" error appears telling that a) the number of host CPUs is 0 (therefore the guest has too many CPUs assigned) and b) no more than 0 storage controllers are available for the selected chipset.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.