Update src/jquery.multiselect.filter.js
Update src/jquery.multiselect.filter.js

Fixed error menu is undefined error on line 32. Changed .data('multiselect'); to .data('echMultiselect');
Added var _self = this; on line 62 of the toggleChecked override function so that the options in the original select get modified when checks get toggled.
PANmedia/ui-multiselect-dropdown,gs-akhan/jquery-ui-multiselect-widget,PANmedia/ui-multiselect-dropdown,gs-akhan/jquery-ui-multiselect-widget,r4j4h/jquery-ui-multiselect-widget,gs-akhan/jquery-ui-multiselect-widget,SomethingSexy/jquery-ui-multiselect-widget,SomethingSexy/jquery-ui-multiselect-widget,GerHobbelt/jquery-multiselect,r4j4h/jquery-ui-multiselect-widget,mcl-de/jquery-ui-multiselect-widget,mcl-de/jquery-ui-multiselect-widget,GerHobbelt/jquery-multiselect,SomethingSexy/jquery-ui-multiselect-widget,mcl-de/jquery-ui-multiselect-widget,GerHobbelt/jquery-multiselect