Reproducible: always

Steps To Reproduce:

1. Enable Menubar and Bookmarks Toolbar
2. Dragging a link onto Bookmarks menu and/or sub-folder so that the menupop open
3. And continue dragging over scrollbutton(top and bottom of the popup)

Actual Results:
The popup would not scroll with Mouse wheel

Expected Results:
Scroll properly

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=8bd696e50a12db4f6be4ded519ef4f97ed6fed60&tochange=bd7cd9d7b6ade7bf9fa8441a8686f19c36f2a7e5

Regressed by:
bd7cd9d7b6ade7bf9fa8441a8686f19c36f2a7e5 Alexander Surkov — Bug 1539651 - Convert places-popup-base and places-popup-arrow bindings to Custom Elements r=mak

hope bug 1572624 will help this one as well

Fixed by Bug 1572624

Hello Alice,

I have tried to reproduce this issue with builds from the following dates: 2019-08-08 and 2019-08-12 but did not manage to reproduce it under any circumstance.

Could you please provide more detailed STR, or maybe check if this issue occurs anymore?

Thank you in advance!

Aha, sorry

Actual Results:
The popup would not scroll with Mouse wheel

This should read as "The popup would not scroll".

I can reproduced on the following Nightly build.
Version 70.0a1
Build ID 20190809095611
User Agent Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

And already fixed on recent Nightly71.0a1 as well as Firefpx70.0b9.

Steps To Reproduce:

1. Add many bookmarks in a folder so that the menupopup will be scrollable
2. Dragging a link onto the folder, so that the folder will open
3. And continue dragging over scrollbutton(top and bottom of the popup)

Actual Results:
The menupopup would not scroll

Expected Results:
Scroll properly

Managed to reproduce this issue as per the above mentioned STR with Nightly build 70.0a1(Build ID 20190809095611).

Confirming as verified fixed on Nightly 71.0a and Firefox 70.0b9 with Windows 10x64 and Ubuntu 18.04.