Composing Mail IE vs Firefox

[iceruam]

I am using the standard version(HTML) of the ZCS, version 5.0.5 on uubuntu.
When composing mail using MSIE, versions 6 and 7, entering text in the body of the email is not possible, Firefox is fine. However, one thing I did find out was that if a user has a signature all is well. I was just curious if others have had this similar problem
Ice