Hi Mo, I still see it on Windows (screenshot attached):

Do you have a different context menu? No context menu? Does it matter whether you are viewing the sidebar in a regular or a private window?

Ah good, thank you. That suggests I'm looking at a MacOS bug, perhaps?

No context menu. Right-click the device as you are, and nothing happens (private or not).

How about the other sidebars like bookmarks or history? Can you summon a context menu there using either right-click or Ctrl+click?

If you are using the updated sidebar (the one with the launcher button bar), and you don't need the vertical tabs feature, you could try switching back to the old design. Here's how:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste sidebar.revamp and pause while the list is filtered

(3) If the preference has a value of true, double-click it (or click the Toggle button or Reset button at the right end of the row) to switch it to false

Yes context menu works within other sidebars like history, etc.

Same issue with 'tabs from other devices' sidebar whether in horizontal or vertical tabs mode.

Just for the avoidance of doubt, I can get a context menu on individual tabs, but not on other devices, so I don't have the option there to open all.

I searched on Bugzilla but didn't see this issue. You could file a new bug: https://bugzilla.mozilla.org/enter_bug.cgi

By the way, that "revamp" toggle is now available on the Settings page:

• Open the Settings page
• In the tiny search box, slowly type sideb until Firefox brings the Browser Layout settings into view
• Un-check (Clear) the checkbox for "Show sidebar"

You may need to move or restore the Sidebars button on the toolbar after making this change.

Example screenshot attached.