Themes using overlay scrollbars have to set explicitly set backgrounds on all scrollable widgets

[Lars Karlitski]

The overlay scrollbar module forces the window that should be scrolled to be native. Gtk is moving away from native windows and seems to have some hard-to-find regressions when using them.

This causes a bunch of themeing issues (black/transparent backgrounds) which can be worked around in the theme by setting backgrounds for these widgets explicitely. That's a performance issue (since we're filling backgrounds unnecessarily) and annoying, as these have to be only some of the time for some widgets (e.g., GtkEventBox).

Porting overlay-scrollbars to not use native windows might be worthwhile if we decide to keep them.

[Sadi Yumuşak (sa-yu)]

I frequently get background color change to black in Nautilus and some other apps, which is very annoying. Themers say they don't want to implement workaround because it's a bug.

[Juliusz Gonera (jgonera)]

Confirming, Greybird looks really bad because of this and its authors don't want to merge a workaround:
https://github.com/shimmerproject/Greybird/issues/64

[Adolfo Jayme Barrientos (fitojb)]

The GTK+3 implementation of overlay-scrollbar has been dropped as GTk+ 3.16 includes a similar feature.

[Amr Ibrahim (amribrahim1987)]

Trusty is affected by this bug.