Crashes when Facebook Container add-on is enabled

[hckr]

Clicking on menu option to create a screenshot causes current Firefox tab to crash.

Reported in Facebook Container issue tracker: mozilla/contain-facebook#662

[hckr]

I found a workaround: using window.wrappedJSObject instead of plain window.

[hckr]

The workaround creates new problems and isn't very handy – it causes problems with messaging between windows via postMessage – responding with e.source.postMessage from popup window to the main window (e.source) fails.

[hckr]

The same issue occurs inside private browsing windows, without any "container add-ons".

[hckr]

Another similar issue: mozilla/multi-account-containers#1771