I no longer see substed drives in XP with #5734 and #5706.
Also if I map a new drive (in Explorer: Tools --> Map network drive) the drive is not seen in Idea. There does not seem to be a way to refresh e.g. the Open project window to be able to see the added drives.
With substed I mean drives created with subst command, like this:
Substed drives used to work in 5.1. I've used them as they seem to be faster than mapped drives on slow connections.