diff --git a/package/lib/src/foundation/sheet_extent.dart b/package/lib/src/foundation/sheet_extent.dart
index b58ce58a..3034db7a 100644
--- a/package/lib/src/foundation/sheet_extent.dart
+++ b/package/lib/src/foundation/sheet_extent.dart
@@ -8,6 +8,7 @@ import 'package:meta/meta.dart';
 
 import '../internal/double_utils.dart';
 import 'sheet_activity.dart';
+import 'sheet_controller.dart';
 import 'sheet_drag.dart';
 import 'sheet_extent_scope.dart';
 import 'sheet_gesture_tamperer.dart';