Hi dohnfors,

Yes, it's part of a tablix

The error is:

The BackgroundColor expression for the text box 'response_perc' referes to the field 'Response'. Report item expressions can only refer to fields within the current dataset scope or, if inside an aggregate, the specified dataset scope.

However the dataset for the tablix is the dataset containing the Response column. The tablix displays the percentages of each response and the response column is displayed within the tablix, so it's defo not out of scope.