Another little Windows usability issue (Suprised? Really!?
All of my sketches are in a Dropbox folder (I use Dropbox as an installed application rather than their web based method), as i'm often on different computers, away on work etc, all the reasons you'd use Dropbox.
Most of the time I use the Mac IDE for development, and can simply select Open > Dropbox, and get to my sketches that way - and saving simply saves them straight back into Dropbox. However, when on Windows - Dropbox isn't a view-able or valid folder to select, attemping to open it's desktop shortcut (as Dropbox dosen't appear in the folder hierarchy) simply gives me the same error as if I'd attempted to open a non .PDE file.
So currently my work-around is to copy the folder from Dropbox onto my desktop, and then when I'm done - the same in reverse. Defeats the point of Dropbox in the first place.