I have a problem when I am typing out a post. It is a bit difficult to describe.
When I reach the botton of the posting window, the window shoots up to about half way and I can't see what I'm typing.

Saundthorp - I too used to have that problem, on Anglican Mainstream and on a predecessor to this forum.  In both cases, I mentioned in on a thread like this and within a few days it had gone - so whether it something that can be fixed from the Admin. end, I have no idea.