- Keep 3px x 3px square separator of Overdrive-mode OSD slider (Gnome-Shell 3.26).
- Updated DashToDockExtension styling for upstream changes (Gnome-Shell 3.24/3.26).
- Tweaked hovered/pressed MessageList background colour in PopupMenu (Gnome-Shell 3.26).
- Added Budgie 10.5 feature (upcoming) "notification grouping" GtkListBox styling (Gtk+ 3.22/3.24/4.0).