That is very odd. Was the paste from another e-mail in your account? Does this still happen?

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

Firefox does allow sites to modify content on the fly when you copy. For example, when you copy from some sites, they add a link back to the site to the end of the content and it shows up when you paste.

It would be extremely bizarre for a site to inject completely unrelated information into the page for copying purposes, so I don't think that's very likely here. Two other hypotheses:

(1) That was hidden content in the selection you copied and it became visible when you pasted; or

(2) Another application overwrote the Windows clipboard between the time you copied and pasted.

I'm guessing the email was in the account of one of the people in my address book. The "hidden content" may have been the case. A strange solution seems to have done the trick as far as random things happening during the use of gmail. I disabled keyboard shortcuts because it seemed like the computer was going to them when I didn't press shift or control. I'd just hit a letter or character and the whole screen would jump somewhere else. So far so good. Thanks for the advice.

Glad to help. Safe Surfing.