I am unable to open projects or files with XCode unless I explicitly do so by going to "File->Open...". If I double click a file or project from the Finder, XCode is launched (or given focus if already open) but it does not load my file or project. Same thing goes for the /usr/bin/open command. This only happens on one of my two development machines and it does not happen to any of the other developers on my team.
I've tried uninstalling and reinstalling XCode (/Developer/Library/uninstall-devtools). I've tried restoring my user settings to default. I've tried different versions of XCode. Nothing seems to work.
I'm desperately annoyed and I'll take any advice at this point.