I'm unsure what you mean "the gtk one. ex. of synaptic's in screens", but I guess the difference is that with traditionnal scrollbar they would take space on screen so nothing would be under them so they would not restrict access to elements...
I'm unsure what you mean "the gtk one. ex. of synaptic's in screens", but I guess the difference is that with traditionnal scrollbar they would take space on screen so nothing would be under them so they would not restrict access to elements...