Highcharts tooltip not sticking to point in datechart
===

I am using the latest version of highcharts (2.25) within a project of mine. For some reason when one hovers over a point on my datechart the tool tip does not adhere to the points position. The video below shows exactly what's happening - I found this example on youtube. It's the same exact issue but no solution is mentioned.

http://www.youtube.com/watch?v=SyiNoDmFR7o

The charts data is coming back as a JSON object which I have validated in JSONlint. So there are no issues with malformed data messing things up. Also, there are no errors in my JS console. 

Here is my default options setting which I have in a PHP class

    $chartsettings = array(
        'chart' => array(
        'renderTo' => 'highchart',
        'type' => 'spline',
        'zoomType' =>'x',
        'backgroundColor' =>'transparent'
    ),
        'title' => array(
        'text' => '',
    ),
        'subtitle' => array(
        'text' => '',
    ),
        'legend' => array(
        'layout' => 'vertical',
        'align' => 'right',
        'verticalAlign' => 'top',
        'x' => -10,
        'y' => 100,
        'borderWidth' => 0
    ),
        'xAxis' => array(
        'type' => 'datetime',
        'maxzoom' => 3600000, 
    ),
        'yAxis' => array(
        'max' => null,
        'min' => null,
        'title' => array(
        'text' => 'Number of Visits',
       ),
      ),
    );

Thanks in advance!

