Gedit warning: GtkScrolledWindow is mapped but visible child GtkScrollbar is not mapped
Solution 1:
It was a bug in overlay-scrollbar which has been fixed here at launchpad. It has been fixed.
So just run
sudo apt-get update
sudo apt-get install overlay-scrollbar
Solution 2:
Until the update has been revised past 14.04, go ahead and reinstall the package:sudo apt-get --reinstall install overlay-scrollbar
Solution 3:
Reinstall overlay-scrollbar .I hope it will fixed your problem .