Wishlist: ScrollBarMargin control reacting to mouse-clicks

[rofl0r]

hi @jonathanslenders

would be nice if one could click on the arrows of the ScrollBarMargin control as used in TextArea to scroll, and even better if one could drag the handle around to scroll.

my naive guess is that it could be sufficient to just add a handler argument to the spots that emit the text fragments like here:

                    ('class:scrollbar.arrow', self.up_arrow_symbol, scroll_up_handler),

[jonathanslenders]

This can be done. (Handling mouse clicks at least. Dragging the mouse is much more challenging.)

[rofl0r]

the primary use case would be to speed up scrolling, because the mouse-wheel scrolling is way too slow (equivalent to hitting cursor-up).
like when you have a text buffer with 2000 lines, and you click on, say the 80% position so you can directly jump there without having to scroll for a minute.