Some users have experienced an issue with copy/paste when they have Webroot Antivirus Software installed. Apparently, things work fine when copying & pasting within Personal Lexicon but the issue shows up when copying from another program and pasting into PL. Also, vice versa is a problem, when copying from PL and pasting into another program.
You can get around the issue by going into “Identity Protection Setup” and in the tab “Application Protection” finding Personal Lexicon and selecting “ALLOW”. I have not done this myself, but thanks to Elias for finding the solution.
If any one else experiences a similar problem with other antivirus software then please let us know.