shade-inactive-windows breaks workspace preview in activities overview

[genodeftest]

When using shade-inactive-windows, in activities overview the workspace preview (right side) is broken for all workspaces but the currently active one. This results in windows disappearing or being only partially painted.

[legluondunet]

I can reproduce this bug: https://bugzilla.gnome.org/show_bug.cgi?id=792258