Div filling out causing scroll in Panel


I posted a question on StackOverflow and was advised by one of the gentlemen in that forum to post it here as well.
My question isn’t probably that hard if you’re experienced with CSS and overall web-development, as I’m clearly not… =\

The question is posted

I hope you don’t mind me linking it but it contains quite a lot of images and code extracts… =P

If you have any input then please post it either here or on SO!

Thank you forum!