Honestly in CDE/Motif/classic Tk styles I actually have a little bit of trouble telling stuff apart, because everything has the same background color. We just r

Honestly in CDE/Motif/classic Tk styles I actually have a little bit of trouble telling stuff apart, because everything has the same background color. We just retired an app that often had like a dozen or so dropdowns and edit fields on top of each other and it was kinda hard to tell where a box was, because all those lines are kinda just noise in a dense interface. The same interface even in Gtk, where widgets have a simpler outline, but utilize colors, is much easier to use. You also can't easily tell read-only widgets apart, because everything is the same color and look (might be a Tk defect though). I suspect CDE was designed to still work on monochrome displays, but color is imho very important for effective interfaces and CDE doesn't use it at all.