Revisit menu button style
Revisit menu button style

Change the style class to .menubutton, to avoid interference
from GtkMenu theming.

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita