I was having a problem with floating two element - both left - hoping that the second element's width would expand to the end.
Original code:
.left { float: left; {
.right { float: left; } // right does not expand to fit the width of the row
Fix:
.left { float: left; }
.right { overflow: hidden; }
jsfiddle.net link here
Reference: http://stackoverflow.com/questions/1260122/expand-div-to-take-remaining-width