Scroll in <textarea> almost working?

[omygoodness]

Hi,
I am trying to implement perfect scrollbar using resizible textarea. I tried both ways: Component and Directive but still, something is wrong/missing.

I prepared a simple example: here

1. Using component approach, I can see rails but the scrollbar is not updating correctly and I can scroll 2px no matter what I do. I tried to use update() method on textarea input but it did nothing
2. Using directive approach, I can scroll properly but I can't see rails because they are created inside textarea as HTML and I don't know any solution for that.

Did anyone successfully implemented this scrollbar within textarea?
Any ideas will be appreciated.