Cannot install addons in full screen mode in Tor Browser 9.5.X

Hi,

I cannot install addons in Tor Browser 9.5.X when I use it in the full-screen mode in macOS 10.15.6. Normally a small confirmation box (see the attachment) shows up under the URL bar when I try to install an addon from https://addons.mozilla.org, but that box doesn't show up in the full-screen mode. The webpage just reloads without doing anything.

I tested with Firefox 68 ESR and I can install addons in full-screen mode. So, this is an issue with the Tor Browser 9.5.X on macOS.

These said, this issue seems to be accidentally resolved in Tor Browser 10 alpha versions. I opened this issue so that it can be added to the changelog.