Keep the selected order in the right side

[glezo1]

As well as {keepRenderingSort:true} keeps the left part options in the order the html was readen, it would be great to have the ability to keep the right-part items in the order the user selected them. [Something like keepChoosingSort : true ] One might thing it can be accomplished by means of up/down buttons, but this isn't entirely true regarding optgroups: when using optgroups, you can move up/down elements within the same optgroup, but you can't move up/down a whole optgroup.

[crlcu]

Hi, I'll have to think of a way to achieve this. If you have something in mind, a pull request will be much appreciated.

[adriandelcl]

Hello,

Thanks for your work. I am looking for this feature also. It would be great.