How to lock the higher thumb of the filter slider at maximum range?

[Dena]

Hi, 

I'm setting the highThumbAtMaximum property of 'state' to true, however, it is not behaving as expected and the user can still move around the higher thumbs.  Any ideas what I'm doing wrong?  Here is my filter:

var today = new Date();

var minDate = new Date();

minDate.setDate(minDate.getDate() - 60);

var dateFilter = new google.visualization.ControlWrapper({

controlType: 'DateRangeFilter',

containerId: 'filter_div',

options: {

filterColumnLabel:'Date',

minValue: minDate, 

maxValue: today,

},

state: {lowValue: minDate, highThumbAtMaximum: true}

});

Thanks,

Nav Dena