Its funny sometimes being experienced we make such mistakes that we never had imagined.
I had to send to form with multiselect values
but these were not getting posted
I was moving values to right box but values were not selected as you can see in previous image above and I was assuming that values are shifted to right box therefore it should be posted too. So, basically values in multiselect list should be selected before posting as following.
So to overcome this issue, I just added a single line of Jquery to code so that all values after moved to right box get selected too.
$('#right_select option').prop('selected', true);