There is a design bug on nopCommerce forum. (This bug is also in the nopCommerce Project > forum section)
If somebody pastes long line of code/text, instead of being wrapped the text goes out of the page width.
Here are few screenshots:
http://img253.imageshack.us/img253/4191/31454349.jpg
http://img26.imageshack.us/img26/1223/54842107.jpg