BUG when renaming a file on a save file dialog box

Hi,

I see this so often that I think it's a bug of the file dialog box
under Windows XP.

The problem is this: I want to save a file in an application. I click
save. Dialog box opens. I enter a name, let's say "a.txt" Before I hit
save, I realize there is already a.txt. So I click on existing a.txt,
click again and rename it to b.txt. File list shows b.txt, save as box
shows a.txt. When I click Save it says "file b.txt already exists." But
Save As box says a.txt? Even if I change the focus, it doesn't matter.
I have to change to name and change it back to a.txt manually to get it
work.

Can anybody confirm this? I think I have to do that so often that it
becomes annoying.

Thanks.