If you pass a DateTime with something else other than yeas,month and day set, there will be no info displayed.
import 'package:flutter_heatmap_calendar/flutter_heatmap_calendar.dart';
HeatMap(
datasets: {
DateTime(2021, 1, 6): 3, // this work
DateTime.now(): 7, // this doesn't work
},
colorMode: ColorMode.opacity,
showText: false,
scrollable: true,
colorsets: {
1: Colors.red,
},
);