Comment 8 for bug 1780790

Created attachment 9017453
Screenshot of the first issue

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0

Steps to reproduce:

I can reproduce this frequently but not yet on command. What I'm doing is normal usage:

- Entering data into the location bar which dropdowns the list of options
- Using the right click and mouseover to open tooltips and dropdown menus on pages

I'm using gnome-shell 3.28.3-0ubuntu0.18.04.2 on Ubuntu 18.04. Firefox is 62.0.3+build1-0ubuntu0.18.04.1. I've had the issue happen in all versions of firefox and gnome shell in Ubuntu 18.04 so far. I did a small test with Unity and couldn't reproduce the issue yet but since it doesn't happen 100% of the time longer testing would be required to make sure it's a gnome-shell specific issue.

Actual results:

Two things are happening that may be separate bugs or not:

- When using an external screen placed on top of the internal one with firefox maximized on the internal screen the URL bar's dropdown would consistently appear on the external screen, completely outside the firefox window, instead of the normal location. Screenshot is attached.

- In what appears to be random chance tooltips and menus are often misplaced on screen. It's common but not fully reproducible. What I see is right-clicking an element on a page or hovering over a link and having the menu/tooltip show up somewhere different on the page. Doing it again immediately after often results in it appearing in the right place the second time. I haven't gotten a screenshot yet.

Expected results:

- The dropdown appearing right below the URL bar
- The menus and tooltips appearing at the mouse location