Well its' Sunday, my day to attack "irritating" software and hardware issues

One of the things I've noticed on my system for several months - in every Forum I've tried to post in - is that once I construct a post which is larger than the small screen "text window" - I get this extremely irritating "redraw" between the text I'm typing below the bottom of the text window - and the center of the window.
Is this normal now? I was thinking it might be a feature to limit long posts - but that's doesn't sound right to me.
My workaround when constructing a post longer than 13 text lines, is to move the process to notepad, then copy and paste into the text window.
Anyone have similar issues - or perhaps know a workaround?
I've checked forum settings but can't find anything...
S~
Gunny