Please switch to using Ayatana AppIndicator

Dear upstream maintainers of onboard,

Please switch over to using Ayatana AppIndicator for rendering onboard's systray icon. In Debian, I recently patched onboard with this patch [1] to achieve this.

If you need a patch that works with Ubuntu's AppIndicator GIR and AyatanaAppIndicator, please enlarge the change and use some try:/except ImportError: magic to achieve the correct behaviour.

In Debian and Ubuntu, we currently switch over to Ayatana Indicators and my patchwork on onboard is part of that shift.

For more info, see
https://lists.debian.org/debian-devel/2018/03/msg00506.html

Thanks,
Mike

[1] https://salsa.debian.org/debian-mate-team/onboard/blob/bffe6360b7e7c12491aa5202641be932e23efbac/debian/patches/1002_build-against-Ayatana-AppIndicator.patch