User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:81.0) Gecko/20100101 Firefox/81.0

Steps to reproduce:

Nothing in specific. Updated Firefox to latest version (81.0 then). Originally posted here: https://elementaryos.stackexchange.com/questions/25745/firefox-or-pantheon-window-render-bug

Actual results:

Double window with a black shadow shows up.

Expected results:

Firefox should have a normal window. With no shadows.

This issue seems to only happen when the window title is shown

That's interesting....can you try latest nightly from Mozilla to check if you see that too? How-to is here:
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems?rd=Bug_info_Firefox#Testing_Mozilla_binaries
Thanks.

(In reply to Martin Stránský [:stransky] from comment #2)

That's interesting....can you try latest nightly from Mozilla to check if you see that too? How-to is here:
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems?rd=Bug_info_Firefox#Testing_Mozilla_binaries
Thanks.

Yes, I tried those methods:

• Refreshed Firefox
• Created a new Profile
• Ran Firefox Nightly

But the double window persists in all the cases. Have a look.

[Tracking Requested - why for this release]:

Change the status for beta to have the same as nightly and release.
For more information, please visit auto_nag documentation.