Note

• Firefox 91.0 and Firefox latest nightly (2021-08-12) not affected.

Affected versions

• Firefox 92.0b1
• Firefox 92.0b2

Affected platforms

• macOS 10.13
• macOS 10.15
• macOS 11

Steps to reproduce

1. Open Firefox
2. Open the Hamburger menu and click on More tools from list then click on Customize toolbar... and then on Done button.
3. Click again on Hamburger menu.

Expected result

• The hamburger menu is correctly displayed.

Actual result

• The More tools section of the hamburger menu is opened and can't be interacted with:
  - can't go back to the main menu
  - can't hover on the list
  - the hover state is stuck on Customize toolbar... menu item
  - clicking on Browser tools opens new window
  - clicking on Web Developer Tools opens Private Browsing window, etc.

Regression range

• This issue is a recent regression.
• First bad: 2021-08-05
• Last good: 2021-08-04
• Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ae11d50c40266fd3413ee79ef86e6ccb1dbbed9c&tochange=e505fffd43c3663a2ed608907ed17830cc526ec9
• Potential regressor: Bug 1722258

Additional notes

• This issue only occurs on Mac OS.

Probably a dupe of bug 1724848 if the latest Nightly isn't affected. Please retest with 92.0b3.

I can confirm this issue is fixed, I verified using Firefox 92.0b3 on macOS 10.15.