No context menu item when shifting focus from a moz-extension tab in one window by right-clicking a website in another one

[u-RraaLL]

Prerequisites

• I verified that this is not a filter issue (MUST be reported at filter issue tracker)
• This is not a support issue or a question
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
• The issue is not present after wholly disabling uBlock Origin ("uBO") in the browser
• I checked the documentation to understand that the issue I report is not a normal behavior

I tried to reproduce the issue when...

• uBO is the only extension
• uBO with default lists/settings
• using a new, unmodified browser profile

Description

Similar to #151. When switching from any moz-extension: tab opened in one window (e.g. uBO's Logger) to a website opened in another window using the right-click, uBO's context menu doesn't appear. Exceptions: Initial Logger launch, and switching directly after using logger's "Reload".

I tried on multiple profiles, ones with other extensions and ones with just uBO. The issue seems to be limited uBO, so it's not a browser limitation (which was my initial thought).

A specific URL where the issue occurs

moz-extension: - github.com

Steps to Reproduce

1. Launch the logger in a popup.
2. Right-click a website - see the context menu item.
3. Switch focus to the logger by clicking on/in the window.
4. Right-click the website again. See no context menu item for uBO.

Expected behavior

Context menu item always visible (like for other extensions).

Actual behavior

Context menu item doesn't appear when switching focus by directly right-clicking a website.

uBlock Origin version

1.42.4-1.42.5b0

Browser name and version

Firefox 99.0

Operating System and version

MX Linux 19.4

[gwarser]

Some timing issue or browser bug.

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It does not seem to happen in Nightly (101).

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Or rather, I cannot repro in my current profile, but I can repro in clean one.