Show full scrollbar only on mouse over
This is a proof of conceptof lighter scrollbars, according to
ideas from the VDG:
show only a tiny placeholder normally, and show the full scrollbar
only on mouse over.
tested on few applications but i know well the
code is just an early hacky proof of concept,
so i'll redesign it as requested.
being a big visible thing, it will probably need
an option as well to make it behave as it used to.
in action https://www.youtube.com/watch?v=O72qxQHjHcw
Reviewed By: hpereiradacosta
Subscribers: plasma-devel, abetts
Differential Revision: https://phabricator.kde.org/D3131