widget needed which widget set provides it?

[Nagy Gabor]

Hi! I'd like to have a widget, just like the location bar of current web
browsers: a combobox, that folds down automatically when the user starts
typing in it, and as he types further, the list of available selections
is filtered according the pattern he's given.

I simply want the user to be able to choose one from tens or hundreds of
names, or to add a new one, and location bars seem to be a very convenient
way to do this.

I always used TkInter so far (not too many times though), and now I checked
python megawidgets, but they do not provide this widget.

Which other widget set do you suggest?

It has to run on unices and windows of course.

Regards
Gee