have a read here for possible solutions. http://ww2talk.com/forums/topic/52239-pasting-text-into-a-posting/
What I always do (to get rid of unwanted bagage) is to paste into Notepad and cut again and paste where I want.
Hi JohnS If you are using Internet Explorer (IE) as your browser I would suggest you change it to another one - personally I changed to Google Chrome and I have not had a problem cutting & pasting since that change. TD