With FF open to a banking site, Excel and other apps (2nd FF instance) will not accept alpha/numeric keyboard input. Arrow keys and enter key still work. Logged out from bank, close the FF window, bring up new tab (Goggle) and type "123" in search bar, then Excel works okay. Also works if I use Edge to get to my bank accounts. Work around #1: save bank page on desktop, close the on-line page, and open it from desktop. Work around #2: Use Edge. Added info: problem is not consistent. Sometimes things work okay, sometimes not.