very slow for long text

I really like this class - it does a lot and on top of it it's simple to use. The only problem I'm having is that for long texts it is quite slow, much slower than other "rich text" or "attributed text" classes that I've tried.

I'm still playing with this, and it could be that I'm doing something wrong, but just figured that I'd let you know and see if you've got any thoughts on this.
