SketchUp Glitches With Firefox on MacBook

SketchUp Free on FireFox Current 101.1 running on a MacBook 13" using High Sierra 10.13.6 (17G14042). * GB Ram 1067 MHz DDR3 NVIDIA GeForce 9400 256 MB.

The most basic tools are misbehaving. Saving components only to have lines and sides missing when I copy & move them. “Push Tool” will not push all of the way through a co-planer object…it leaves the opposite side without cutting through it. When using Rotate tool; after the move is completed, I must hit “Return Key” three times, then the same number of hits on the “ESC” key, or else the rotated object sticks to the cursor and flies all around the screen.
I have refreshed the browser several times, cleared the cache twice, restarted the MacBook twice…NO JOY! What is going on??? This hasn’t happened before.