I filed a bug in Beta on that mouse selection thing too. Specifically, I have a problem with the whole row in details vew being selectable now. I'm sorry MS, but 16 years of rubber-band selecting of files is hard to unlearn. I'd love to see the user testing that shows how clicking in empty white space (especially between file names and the next column over) is more intuitive. To me it just irritates to no end and increases the chance for "Oh sh*t where'd my files go now?!?" moments. Thumbs down on that particular innovation.