Firefox annoyance during downloading files

[James Pifer]

I'm on Mozilla Firefox version 1.0.7 on FC4. I've had an annoyance that
started a while ago, but not sure how long ago or what version. Here's
what happens:

-Click on a link to download a file 
-Select Save To Disk and click OK
-Click Browse for other folders
-Browse to where you want to save it
-Click Create Folder
-Type name for the new folder and click on it to open it

At this point the file name of what I'm trying to download disappears
from the Name field. It's very annoying and I've verified that I do not
have the same problem with Mozilla. 

Anyone else seen this before and know of a fix or what's causing it?
Sorry if it's been asked before. 

Thanks,
James