For some unknown reason, my Gmail has suddenly begun overscanning so I have to scroll side to side to read a message. I tried reducing screen size but in order for it to fit the screen the type was almost too small to read.

Any suggestions??

While on the topic of Gmail: I've also recently had the problem of attachments like pictures disappearing from previously received and viewed emails that have not been deleted. I never had this problem before.

Once again; suggestions welcome.

This is killing a mouse with a wrecking ball, but it might be worth reinstalling the browser(s) you use. Also change Gmail password.

With the overscrolling issue only, it should be possible to click 'reply' before you read each message, then the message will be neatly formatted below the space for your answer

Same problem w/ Google Chrome - not mouse - their problem not mine - dumped Chrome returned to Firefox - also use Thunderbird for mail - only go to gmail main site to periodically trash and clean. Confidential pics and attachments s/b saved to separate folder in case gmail main compromised. Do not believe security assurances from sites, always some teeny bopper hack out there smarter than experts. Take your own precautions concerning files you want to save for future use. PC use is like love don't believe promises and always watch your back when partner is chopping onions with big knife.