The problem is with all Word documents I receive as attachments to emails. I've sent an email to myself with two Word attachment, one I created and one someone else created, both open with the problem.

If I save an incoming Word attachment, then open it it's ok?

"There is an odd dropdown arrow under the paste button and above the tab type indicator - what does that do?" It brings up three paste options.

I'm going to run an Office repair, I'll let you know what happens.