* There were two bug reports of NullReferenceException on line:
hoverWin = m_HoverNode.OwnerView;
* Which doesn't make sense since m_HoverNode must be non-null to go by
the lines above, and all the callbacks should run on the UI thread so
it can't be a race.
* Caching locally and checking for OwnerView/ListView being valid might
fix the crash. Hopefully!