One thing that always bothered me with megaglest scrollbars is that whenever we're out of the scrollbar "bounding box", nothing happens: it's not lighted, and it doesn't move. This means users will stop moving it, and will try hard to stay inside the "bounding box". This is not expected of scrollbars, and I believe megaglest scrollbars should work the way every other scrollbars work.
My patch has two main parts: the first one updates components.cpp where the scrollbar code lives: the new logic makes use of mouseUp() to know when to stop changing the scrollbar position. The second part simply makes sure that the mouseUp() event reaches every scrollbar (scrollbars exist in four different menus).
Thanks for megaglest.