jScrollPane is a neato custom scrollbar plugin, but it won't unbind drag mouseup events correctly within a Google Maps container (it binds these events to html and the unbind never fires). The following resolves this.

jscrollpane-mouseup-fix.js

$('.jscrollpane__container').jScrollPane().bind( 'mouseup.jsp', function () {
    $('html').unbind('dragstart.jsp selectstart.jsp mousemove.jsp mouseup.jsp mouseleave.jsp');
    
    // This will remove the active class from ALL windows, so keep that in mind
    // if that isn't the desired behavior.
    $('.jspActive').removeClass( 'jspActive' );
});