Bootstrap - maintaining column widths using position:fixed?

Fixed position is relative to body, so it will count the 100% width from body width. If using javascript is ok, you can set the sticky width by getting the container width. Check the Updated Fiddle

add:

width:inherit;

to your .sticky.stick

JSFiddle

like Nanang Mahdaen El-Agun said, a fixed position relates the width to the body. With width:inherit; it will use the width of the .container class

reference: Set width of a "Position: fixed" div relative to parent div