Recently I had to make some impromptu updates to my computer, in order to be able to use zoom for doctor appointments. This introduced some side effects; I think it may be a Firefox problem, but I can no longer outline a big table of raw text and use the mouse to go to browser edit menu and say "cut" and have anything happen. I started erasing a big table of output in the answer linked above. If anyone could finish erasing that section, it would be a big help.
Related: I can no longer use the mouse to copy paste here, or on gmail, anything on the browser. I can copy and paste between (Ubuntu) gedit windows and terminal windows, so creating and running C++ programs is fine. It is just that I must currently outline the text and then click on the middle wheel of the mouse, and results are a bit unpredictable.