Hello Ken,

When a PivotGrid is used the columns are created dynamically depending on the data.
It is not recommended to use colnames to add labels.

You can use setLabel java script method to set the label names in columns, but you will need to know the name of the column from colModel, which is generated dynamically too.

I know there is a little problem with the labels on the grouping headers and thin we will fix it in the next release.

Kind Regards