Steps to reproduce

1. Click and drag minimum value handle to the right of the maximum value handle, about the distance in the screenshot (1920x1080 resolution). This distance is greater than (or equal?) to the length of the bar if you were at the maximum range.
   
2. Note that the minimum handle value becomes max minus maxRange.

Demo: http://jsfiddle.net/udL8nhce/3/

Expected behaviour

Minimum value slider should stay at its current value, and not go past provided range.

Actual behaviour

Minimum value slider goes to unexpected value outside of available ranges.