Doesn't handle files without extensions.

Try to attach a file using Mac OSX (may or may not happen on other OS, untested) that doesn't have an extension. In particular, I used an OmniOutliner document. Clicking add causes a "browser blink" but nothing else. Even worse: the submit, preview and add buttons will not work until you use the browse button to select another file.

I noticed that my {browser||OS} added an .oo3 extension to the file in the file name box, but the file doesn't show with that extension on my system.

I have no idea what the issue might be or where to find it. If anyone wants to take a look at this or suggest ideas, please do. This bug might actually be in Filemanager, not Attachment. I'll eventually look into it, but for now I'm just documenting.