I am not using IE at all, but just out of curiosity decided to try in IE8.
I modified one of my posts
The behavior was really a bit weird, but not completely as you described.
You said when you scroll down it "will not stay in view".
In my case when I scroll and place cursor where I want to edit the input box kinda was refreshing. The content will scroll up and down... but it was returning correctly to the position where the cursor was previously placed. So, basically I could continue editing.
That is just annoying indeed
The cure as I found is to display Comodo pages in Compatibility View
You can try that.
I tried several other forums - there were no jumping/refreshing during editing.