Shift Right click opens browser context-menu on Firefox

[VelorumS]

Describe the bug
Right mouse-down with Shift held opens context menu on Firefox.

To Reproduce
Steps to reproduce the behavior:

1. Hold Shift.
2. Click the right mouse button.
3. See the context menu of the browser near the mouse pointer.

Expected behavior
There should be no context menu shown.

Client:

• OS: Linux
• Browser: Firefox
• Browser version: 106.0.5

Server:

• noVNC version: 2d6302e
• WebSocket proxy: websockify

Additional context
No bug on Chrome.

[CendioOssman]

I'm afraid this is a "feature" on Firefox:

https://bugzilla.mozilla.org/show_bug.cgi?id=1467158

As such, there isn't anything we can do at the moment. :/

Hopefully, Mozilla will reconsider and provide some way for us to handle this.