I have this simple jQuery UI Slider setup with a range and a two default values that overlap. The entire thing (with a few bells and whistles) can be found in this jsfiddle:
I'd say this is a bug, doubly so because there's already logic preventing a ‘deadlock’ from happening when both slider handles are at the minimum / far left position:
// workaround for bug #3736 (if both handles of a range are at 0,
// the first is always used as the one with least distance,
// and moving it is obviously prevented by preventing negative ranges)
if( o.range === true && this.values(1) === o.min ) {
index += 1;
closestHandle = $( this.handles[index] );
}
It looks like ticket #3736 is still open, with mentioning of the specific problem you're seeing.