ComboBoxItem / SelectItem + RollOverCanvas / setShowRollOverCanvas possible?

Hi Isomorphic,

is RollOverCanvas as part of a ComboBoxItem (or SelectItem) that I set up with setPickListProperties(ListGrid with @Override getRollOverCanvas) possible? It does not work for me currently and I'm not sure if the error is on my behalf or if it is not possible at all.
This most likely relates to this question.

I'm using current 5.0p.

Thank you & best regards
Blama