use a GtkEventBox & don't recolors the icons.

The icons are being recolored whenever the export dialog post backdrop state
Disable that as we don't need it.
4 jobs for master in 9 minutes and 51 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Lint
passed #429046
rustfmt

00:00:20

 
  Test
passed #429047
flatpak

00:09:03

 
  Review
passed #429048
review

00:00:28

manual #429049
allowed to fail manual
stop_review