This is the last fix needed for this.
The issue is that command events now are triggered by synthetic click
events (which was not the case before pretty much by chance, a side
effect of how these events were implemented).
If we open a panel by a command event triggered by the synthetic click
event, rather than the real keypress event, we end up not detecting that
it is really a keyboard activation, and not focusing the first navigable
element in the panel for example, which is unfortunate.
This was caught by browser_toolbarButtonKeyPress.js.
We could keep the old behavior of not triggering commands from
dispatchEvent()-ed clicks, but honestly that's kind of bizarre.
Differential Revision: https://phabricator.services.mozilla.com/D157596
20021a15f0