one trick that may help you (if you know the name of the file to be attached) is to start typing the name, this will then narrowdown the files in the drop down to those starting with 'XXX'. Use this all the time. YMMV

Hi - if there is a chance to include this  feature in upcoming version 5, it would be great:  

make the overall size of the attachment window much bigger - so more of the hard drive is visible.  

Even better would be a way to save a custom size, as one can do with the main windows of Pegasus.  Every time I add an attachment, either I have to scroll around a lot, or stretch the attachment box, or click in it´s top ribbon to make it full screen.  I think this has to do with one of Windows default window size settings, but as all the main windows can be resized and retain the settings, perhaps eventually, the attachment box can as well.

 Pegasus still rocks - showed a friend this and he shifted immediately from Outlook 2010.....