Web-extension functions correctly on Chrome and Opera but not FF?

I recently converted my addon to web-extension, the addon works perfectly for the first page load or full-refresh on all browsers but when navigating to other videos on Youtube the download button is visible only on Opera and Chrome.

What am I missing here?

Is navigating to other videos on youtube actually a page-load? maybe its an ajax change, so you might be missing a load event.

It’s an ajax event but the same web-extension code works on Chrome and Opera???

Add to that the same code worked beautifully with FF before switching to web-extension!!!

Adding an event-listner for spfdone event (http://youtube.github.io/spfjs/documentation/events/) fixes the issue but the question remains why the same code worked earlier on FF and still works on other two browsers?

I suggest you file a bug report for this issue.

Done - https://bugzilla.mozilla.org/show_bug.cgi?id=1365885