Template Builder: Not possible to put Charts in groups

I try to put a Chart in a group by selecting "Chart is inside group" for the chart.

When I do this, no Chart is rendered (Only default image is shown). The "Preview" button in the chart Wizard is also disbled when  "Chart is inside group" is checked.

I use the Wizards in Word "Template Builder" (11.1.1.5.0, build 174), not the WYSIWYG designer. (The reason for using Template Builder is that I want to use advanced properties like reference lines, transparent colors etc)

Please advise me how to resolve this. I attach images of the data-model (simplified test-data), the settings in the Wizards and the result.