i have Dell G7 with geforce 2060 and latest drivers with latest Elementary i have black shadow on letf and top when web aplication opens new firefox window. on java mouse is not sinhronized with java-fx window cursor marks clickable top left edge of window.
This is still happening as of November 14 with Firefox 82.0.3. There's a mozilla thread about it that indicates that it's an elementary-OS-specific issue and that it's a regression. They've been kicking the can down the road by marking the problem as "wontfix" for each successive Firefox version rather than addressing it. If this is specifically an elementary OS problem, can the underlying cause be fixed in the OS?
There is a workaround: in the file
/usr/share/applications/firefox.desktop change the line
Exec=firefox %u to
Exec=env GTK_CSD=0 firefox %u. Found this solution at https://www.reddit.com/r/elementaryos/comments/j3h3fp/firefox_users_anyone_seeing_an_issue_where/