I had the same problem with Steam after last update Gtk-Message: Failed to load module "overlay-scrollbar".
I did search and found this hint: clear steam cache previous installation by on terminal
rm -Rf ~/.steam/steam/appcache
and install again by steam .deb from steam website.
I hope help to solve the Steam problem by "overlay-scrollbar"
I had the same problem with Steam after last update Gtk-Message: Failed to load module "overlay- scrollbar" .
I did search and found this hint: clear steam cache previous installation by on terminal
rm -Rf ~/.steam/ steam/appcache
and install again by steam .deb from steam website.
I hope help to solve the Steam problem by "overlay-scrollbar"