I have been using Atlas in QGIS without any Problem. In one Atlas I could "filter" the objects that have to be displayed in the map with a "rule" for color' assignment. this rule combines the @atlas_featureid (current section to be displayed) and the id in that step. If the numbers are the same then the red polygon will be shownd.
However in a report @atlas_featureid doesnt work (or I dont know how to make it work).
Is there any equivalent code for a (let's say) @report_feature_id???