Choose a Firefox update channel
Firefox ESR release cycle
suggest to me that ESR release may be up to a year behind on new features.
Fortunately there was also a Duplicati code change to adapt to a missing one:
New UI: Context menu opens outside the frame #423 has discussion about it.
Question then becomes how to get that fix in something safer than a Canary?
https://github.com/duplicati/duplicati/blob/release/beta-2.2.1.0/Duplicati/Server/webroot/ngclient/package.json
looks like it got ngclient 0.0.207 and is a Stable release candidate described at
Release: 2.2.1.0 (Beta) 2026-03-05
https://github.com/duplicati/ngclient/blob/main/package.json
0.0.207 was Feb 20, so it seems like it should include the fix claimed on Feb 16.
Since the non-ESR Firefox already has the needed feature, the only people who can test workaround for browsers lacking it are those on one. Care to test it out?
explains why 149 is OK, and actually 147 was too (if I’m reading all of this right).