Steps to reproduce:

1. Download a file, for example by opening a new tab and choosing "Save Page As..." from the in-content context menu.
2. After the page has been saved, open the downloads panel.
3. Right-click on the download.

Expected results:
The set of items should be: Show In Finder | Go To Download Page, Copy Download Link | Remove From History, Clear Preview Panel

Actual results:
There are a number of extra items at the start of the menu:
Pause, Resume, Allow Download, Open In System Viewer, Always Open In System Viewer

This is a result of https://searchfox.org/mozilla-central/rev/37edd2782e67e716dd07a85016da07b4d6275e5d/browser/components/downloads/content/downloads.css#39 being used to control menuitem visibility, and (the wontfixed) bug 1700732.

To fix it we'd need to re-encode the logic from the CSS into hidden attributes, I assume. Markus, is that right?

Ah, I suspected something like that, thanks for tracking it down. Yes, this would need to be changed to use hidden attributes.

Prior to figuring out the CSS thing I was hoping bug 1707204 would just fix this, but I guess there's more to do then. I'll take a look on Tuesday if nobody beats me to it.

Set release status flags based on info from the regressing bug 1700679

https://hg.mozilla.org/mozilla-central/rev/f13af8d47dca

Comment on attachment 9218710 [details]
Bug 1707652 - fix display of download context menu items with macOS native menus, r?mstange

Beta/Release Uplift Approval Request

• User impact if declined: Required for MR1 / Proton, if bug 1700679 is uplifted.

Uplifting this prior to bug 1700679 would be fine (ie there's no hard dependency).

• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: See comment 0.

Note: to reproduce the bug, widget.macos.native-context-menus needs to be set to true. This is not yet the case on beta, but will happen once bug 1700679 is uplifted.

• List of other uplifts needed: Bug 1707204
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This moves logic that hides some of the context menu items from CSS into JS and de-duplicates it. There is an automated test that verifies some of that behaviour, and verifying manually that we don't display 10 items, half of which don't apply, on macOS anymore should be straightforward.
• String changes made/needed: Nope

This won't reproduce on beta except when the native macOS menus are enabled. Doing that by default is bug 1700679 which already has a pending uplift request. Going to set beta as affected to ensure this bug shows up in uplift queries; it should be fine to uplift it either prior to bug 1700679 or afterwards.

https://hg.mozilla.org/releases/mozilla-beta/rev/6d49416e440f

Comment on attachment 9218710 [details]
Bug 1707652 - fix display of download context menu items with macOS native menus, r?mstange

This was uplifted along with bug 1700679.

This issue is verified fixed using Firefox 90.0a1 (BuildId:20210504214950) and Firefox 89.0b8 (BuildId:20210504185920) on macOS 10.15