Firefox invokes Nautlus under KDE . . .
 

as its default file manager. This works as a file manager, but causes a small problem: When Nautilus is running under KDE, it forces the GNOME desktop to be displayed. Now that's not too much of a problem, except that Nautilus does not terminate when the Nautilus window is closed. Which leave you with a GNOME display and a KDE bottom panel. To revert to KDE, I have to manually kill the Nautilus process.

So, two related questions:

1) Is there any way to specify the file manager that Firefox should open when it needs a file manager? (I couldn't find anything in the Firefox site, nor in the config.js file.)

2) If not, is there any way to configure Nautilus so it will terminate when its window is closed? (Again, I failed to find any clue in the GNOME documentation.)

(Oh, if it's not clear, an example of a file manager invocation in Firefox is when a window is opened for the user specification of an download file name and location.)

I'm not sure about firefox...what sort of action is opening up a file browser? If you know what does it, I can poke around in my settings and see what happens when I do it since I sure as heck don't have nautilus installed. (nevermind, I just saw that you said it already above, I just missed it)

But for nautilus itself, if I remember rightly, using
nautilus --no-desktop
will prevent it from running the Gnome desktop when you start it. (I had the same problem, and hated it just as much :) Tried to install nautilus temporarily now to double-check myself, but got fed up with dependancies. So I'm just 95% sure that's right :))

Ok, the firefox documentation says that it opens that particular window using the "Default file manager" of the system. As you've got both KDE and Gnome installed, I'm guessing that Gnome took over this particular aspect of your system's configuration before KDE could say anything about it.

Google's giving me the impression that in the KDE control center ("Kontrol Center", I think?) there is somewhere a section on the File Manager...maybe you'll be able to change it in there? If that fails, try looking though the gnome control center, and trying to disable nautilus there.

Either that, or just uninstall nautilus. KDE has its own file manager which it ought to be able to use just fine.

Well, the KDE "Control Center" does have a "File Manager" item, but all that does is let you specify what fonts, etc., the file manager uses. And the "Component Chooser" has no "File Manager" setting.

And to confuse things further, I've set my GNOME file manager to XEMACS, so I've no idea what Firefox is looking at to find the "default file manager." I just looked at the "set" output, and there's no variable defined for "file manager." In fact, here's what I have:Any idea where I should look for the "default file manager" setting?

Haven't the faintest, honestly... Any KDE/Gnome users reading this???

What happens if you uninstall Nautilus? (put it back afterwards if it's an application you use, of course.)