GTK3 huge status bar padding workaround

[drws]

Expected behaviour

GTK3 uses a 10px status bar padding which looks huge on lower-resolution screens and eats up precious vertical space in any case (16:9 screens...). GTK4 reverts this, but in the meantime, the standard GTK3 system-wide workaround seems to be to work around the issue in the theme.

Actual behaviour

The following screenshot was taken from a system with MATE 1.26.0 that uses the BlueMenta theme (and has a 720p screen):

Steps to reproduce the behaviour

1. open any application employing GtkStatusBar
2. take a look at the status bar padding (height)

MATE general version

1.26.0