Steps to reproduce:

1. Go to https://www.flickr.com/photos/mhoye/50305446521/
2. Wait the page is fully rendered
3. Click on the arrow pointing downward on the right hand below the image.

Expected:
Show a modal popup with image size available to download

Actual:
Nothing happens.

Discovered in Firefox Nightly. We have already backed out String.prototype.item, but this problem still persists. Manually doing delete Array.prototype.item; in the JS console fixes it.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1669867.