No! Fwiw, there's a bit too much of it, but it's not even close to the offendingly huge margins of some modern UIs (not arguing there's no place for this UI style at all).

The main window on the first shot from the site is about 620px wide and I feel I could write some code not even resizing it. I easily imagine 2 buttons, dropdown and 2 textboxes filling this whole window instead.