Thx for the example.
The
cellInst.getDataValue("amount_DateGroup/quarter_ProductGroup/PRODUCTLINE")
line helped me a lot.

Is it possible to make the comparison of with data which is not contained
in the datacube?

if( cellInst.getDataValue("PRODUCTLINE") == - field not in the datacube -
){
//set color to bluegray
cellInst.getStyle().setBackgroundColor("RGB(169,170,226)");
}