Shawn Quinn - 2011-09-29

Sorry it took awhile to respond to this issue, but the root cause wasn't obvious so I needed to find some additional time to investigate. It turns out this was happening because of an issue in the Highcharts javascript code. Within Highcharts there is a function defined like so:

function splat(obj) {
    if (!obj || obj.constructor !== Array) {
        obj = [obj];
    }
    return obj;
}

As you can see, that function is attempting to convert the object to an array if it detects that the object is not already an array. The problem comes in from the fact that GWT runs everything within a different context (via an iframe that is injected into the page.) So, the check "obj.constructor !== Array" is always true, because the "Array" type in the context that the Highcharts JS code is running in is different than the "Array" type in the context that GWT is running the code in.

Detecting if an object is an array across different contexts properly is complicated (you can read more about one solution here: http://javascript.crockford.com/remedial.html ). However, a fix that I believe should work for most Highcharts users is if you simply replace that function with the following:

function splat(obj) {
    if (!obj || (typeof obj.length == 'undefined')) {
        obj = [obj];
    }
    return obj;
}

I plan on following up with the Highcharts authors to see if they'll consider including a change along those lines in a future Highcharts release. But, in the meantime, you'll need to change that in your version of the JS file. I also just discovered there is a related post here:

http://highslide.com/forum/viewtopic.php?f=9&t=11268&p=55557

Can you let us know if that clears up the problem you're seeing?