windows live mail cannot paste text when in rich text format

When I try to paste a clip from a website and paste it to an email, it is not visible in the email form as long as the message format is rich text.  If I change the format to text then the text appears.  This only happens when the website attaches the URL of the site to the clip being copied.  Not all web sites do that.  I am running xp sp3, firefox, and windows live mail.  I have IE 8 installed but seldom use it .  I shut down the firewall and antivirus and condition still exists.  Clipboard is running and the text clip selected appears on the clipboard.   No new programs recently added.  Cache and Temp files deleted.  I can paste the clip to Notepad and then copy it there and paste it into the email.  Has something to do with the URL being attached, I believe. 

All suggestions welcome.

Thanks