Fix JS error when menu is closed and alt key is pressed

[GuillaumeGomez]

Here's how I trigger the bug:

1. Open a topbar menu.
2. Close it by clicking on text in the document
3. Press the alt key.

Now the fun part: it doesn't happen all the time so can't really write a GUI test for it. ^^'

[syphar]

I can still reproduce the error with these changes, or is it just another place?

( I tried with the "About" menu )

[syphar]

Also, the real question is:
how did you end up discovering this issue? 😄

[GuillaumeGomez]

I can still reproduce the error with these changes, or is it just another place?

( I tried with the "About" menu )

Hum, weird. Gonna test some more then.

Also, the real question is:

how did you end up discovering this issue? 😄

A human needs to have their secret. 😛 (I literally just saw an error after switching windows when working on #2847)

[GuillaumeGomez]

Ah indeed. So parentNode can exist without having classList. Ok whatever, it's JS.