Screen resolution glitch after 18.04 upgrade

OBJuan here. I’m a new Ubuntu user. Started on 17.10 and recently moved to Ubuntu-Mate 18.04. Great system right off the line but have a glitch that developed in the last 10 days. At boot the desktop is too big for my screen (HP pavilion f70). The res is initially at 1280X1024. I toggle first to 1152X864 &apply. This brings the bottom panel onto the screen. Then back to 1280X1024 & apply. This results in the right side returning to the screen while the bottom panel now stays on the screen. So I’m at the boot resolution but all my desktop is now on the screen. This did not happen for the first few weeks,
Any insights ?
My computer is a home build desktop
Asus - A68HM-E Mother board
AMD A4 7300 processor
4 Gig RAM
Mostly from Tiger Direct