One thing that might be worth trying, by default Firefox now uses GPU accelleration, and on many systems, especially if they are not 'high end systems' or a few years old, this can lead to problems like slow downs or ghraphic glitches.
One thing that might be worth trying, by default Firefox now uses GPU accelleration, and on many systems, especially if they are not 'high end systems' or a few years old, this can lead to problems like slow downs or ghraphic glitches.