listview crash fix

[Dimi Paun]

From: "Michael Jung" <mjung at iss.tu-darmstadt.de>
> Thanks, seems to work fine for me (no crash while browsing about 50
> directories).

Good, thanks.

> I've attached another patch, which fixes the crash in the file dialog
applying
> this scheme. I've only changed as much as necessary to fix the problem,
> though.

Yeah, this is one solution, but it pretty much means that after every
function call we need to check the hwnd for validity. That's not really
nice, to say the least. Give me a bit to get a chance to work on it.

-- 
Dimi Paun <dimi at lattica.com>
Lattica, Inc.