I'm trying to extend datacolumn to work around bug 2652 - There is no way to create certain charts when XML driving charts has certain structure - and my extension will *not* work because of the way dataseries is implemented.

I created a "newdatacolumn" class that allowed datacolumn's values to be set by passing in a function that returns an array of children rather than an xpath. My new datacolumn will not work inside a dataseries because of the way dataseries checks for class -
                if((this.subnodes[i].classname == "datacolumn") && (this.subnodes[i].name == name))

This type of check happens in a few places in the charting code.

What it *should* do is use instanceof for class checks. This would enable users to extend charting classes. i.e. -
               if((this.subnodes[i] instanceof datacolumn) && (this.subnodes[i].name == name))