Why do my Twitter Bootstrap form fields overflow their well using fluid container?

Question

UPDATE: Demo of problem here: http://jsfiddle.net/fdB5Q/embedded/result/

From about 767px to 998px, the form fields are wider than the containing well.

Smaller t

Answer 1

As indicated by Pavlo in this answer: Twitter Bootstrap: Stop input field extending beyond well

Using the class input-block-levelin place of the input-xlarge (or other sizes) solves the problem as well.