Provided in this pull request is a modification to remove the horizontal scroll bar that is unwanted.
Fix RTL horizontal scrollbar issue
The reason we don't use display: none is because really large selects will render very slowly in this way. Position is much, much faster. The fix proposed in #447 is the right way to go about doing this (adjusting to a positive 9999 instead of negative for RTL pages).
I am using an auto sized iframe which includes Chosen selects,
it took me quite a while to find out why the iframes always got a width of 9000.
Adding an option to use display:none would be appreciated by me.