A * selector applies to all widgets, so even GtkBox or GtkGrid - and most importantly GtkListBoxRow - need to recompute their style because of the * selector.
By using a more specific one, these common cases aren't affected anymore.
Fixes slowdowns in gtk3-demo's listbox demo and in gnome-software.
34941ef Adwaita: Make selector more specific
gtk/theme/Adwaita/_common.scss | 7 ++++++-
gtk/theme/Adwaita/gtk-contained-dark.css | 2 +-
gtk/theme/Adwaita/gtk-contained.css | 2 +-
3 files changed, 8 insertions(+), 3 deletions(-)
Upstream: git.gnome.org