Affected versions

• Firefox 88.0b5
• Firefox 89.0a1

Affected platforms

• Ubuntu 20.04
• Windows 10

Steps to reproduce

1. Launch Firefox and have a new tab opened
2. Right click repeatedly over the <- and -> icons from the toolbar

Expected result

• No context menu is shown as no tab history is recorded

Actual result

• A context menu with "new tab" is shown for a split second

Regression range

• Seems to be introduced recently, the issue is not reproducible on 87.0a1 (2021-02-02)

Additional notes

• The issue can be seen in the attachment
• macOS doesn't seem to be affected

(In reply to Catalin Sasca, QA [:csasca] from comment #0)

Regression range

• Seems to be introduced recently, the issue is not reproducible on 87.0a1 (2021-02-02)

Using mozregression I was able to determine the regressor for this bug:

Last good: 73339fe01d1bbfbaba90dfb79972da63e56f8391
First Bad: c840a269bd87e8f247936de20d40c26d9b30a715
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=73339fe01d1bbfbaba90dfb79972da63e56f8391&tochange=c840a269bd87e8f247936de20d40c26d9b30a715

Bug 1670808 - Right-clicking the back button doesn't show the previous pages drop-down menu after new tab is opened

Does this reproduce with 'fission.sessionHistoryInParent' set to true?

I expect that it does not and this bug will fix itself when we eventually turn that setting on.

Yes, it does seem to not be reproducible with 'fission.sessionHistoryInParent' set to true

Removing proton blocking bug as this is not related to proton work.

Then I'd suggest we could just wait until session history in parent is done. Bug 1670808 is a more useful fix to have than a minor flicker.