Some browsers (firefox) fire additional actions on keyup, which conflict with the keydown listens.
Some browsers (firefox) fire additional actions on keyup, which conflict with the keydown listens.

GerHobbelt/jquery-multiselect,r4j4h/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,mcl-de/jquery-ui-multiselect-widget