One problem that I still have not figured out is: why does the combo's dropdown list close as soon as I type any character?

Uhhmmm - something in your code? This is not native behavior.

I did just discover that incremental searches are governed by the new _IncSeek system var (used to be _DblClick) and thought maybe the default of .5 was my problem. But increasing it to 4 seconds did not help.

_Incseek affects Incremental searchinf when the combo's style is 2-dropdown list.

I do not understand why you do not use the combo classes that are on my web site> They work properly.