User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

With a page that placed scroll-behavior: smooth on the HTML element, other elements on the page that had position: sticky no longer "stuck" to the top of the viewport. When I toggled Off the scroll-behavior rule in the Inspector, the sticky elements all worked as expected.

Actual results:

scroll-behavior: smooth prevented elements with position: sticky from actually sticking once they hit the top of the viewport.

Expected results:

Elements with position: sticky should behave as sticky dictates — adhere to the top of the viewport and stay in view as other things scroll under or on top of the element.

Video of the bug in action and how it can be reproduced/resolved in the Inspector: https://www.dropbox.com/s/f5mwzh7k1jhhzw1/Firefox-Bug-Scroll-Bahvior-Position-Sticky.mp4?dl=0

Can you please provide the html in question?

I am guessing this bug has been fixed by bug 1560237.

Yes, that other files bug that has been resolved looks to be the same thing I was seeing. A search for this behavior before I submitted my own report did not bring this issue up, so, sorry about the duplication. I read over https://bugzilla.mozilla.org/show_bug.cgi?id=1560237 and the HTML/CSS to reproduce it all seems to be the same. I have not created a reduced test case yet but this would be how I would go about it.

I believe this ticket can be closed in favor of the previous one.

Thanks J. Hogue. You don't need to say 'sorry' for that. Bugs are quite cheap, whereas, I understand filing bugs isn't so fun for users, bugs filing by users are quite important for us. Thanks for filing this bug!