firefox-91 display problem
by Rod3775 from LinuxQuestions.org on  (#5NG58)
	On upgrading to Firefox-91, the background of a right-side scroll bar is no longer properly displayed. The slider is OK, but the background is garbage.
Prior to the -91 upgrade, there was a problem with the background of a large newly-opened blank window being garbage, but it was a one-time thing that resolved as soon as a Firefox window refresh occurred. Only a "default" (old laptop size) portion of the window was accurately displayed. My actual screen is 1920x1080, but I open Firefox in less than full screen. I ignored this earlier problem because it was transient. The -91 scroll bar display issue is permanent. I reverted to a Slackpkg for firefox-87.0 from March 2021 and both problems went away. No other programs with scroll bars and sliders exhibit this problem AFIK. And no other program that opened a large but less than full-screen window (Thunar, LibreOffice, etc) exhibited the earlier problem. 
  
  
  
 

	
Prior to the -91 upgrade, there was a problem with the background of a large newly-opened blank window being garbage, but it was a one-time thing that resolved as soon as a Firefox window refresh occurred. Only a "default" (old laptop size) portion of the window was accurately displayed. My actual screen is 1920x1080, but I open Firefox in less than full screen. I ignored this earlier problem because it was transient. The -91 scroll bar display issue is permanent. I reverted to a Slackpkg for firefox-87.0 from March 2021 and both problems went away. No other programs with scroll bars and sliders exhibit this problem AFIK. And no other program that opened a large but less than full-screen window (Thunar, LibreOffice, etc) exhibited the earlier problem.