When I use gedit, there is warning shown:
(gedit:3166): Gtk-WARNING **: GtkScrolledWindow 0x236cd10 is mapped but visible child GtkScrollbar 0x2307ab0 is not mapped
How can I fix it ?
It was a bug in overlay-scrollbar which has been fixed here at launchpad. It has been fixed.
So just run
Until the update has been revised past 14.04, go ahead and reinstall the package: