[da-anda]

I'd make the "browse for source" dialog narrower, people with file and foldernames that long that they needed such long lines need to be punished
Also, while the positioning is somewhat fine, I don't like that you don't recognize the buttons right away as such (mabe it's just the screenshots, don't know). I see two solutions to this: give buttons a different color (blue maybe) or give the the column they reside in a slightly different background color (greyish maybe)

edit: @BigNoid
looks like a bit too much of wasted space