diff --git a/travo/dashboards.py b/travo/dashboards.py
index 28d3d77a09cb0a6f1b4fa37aaf55f1f6d77ba31e..e8bc140bec54c624ae387e09cec455f9cd1049a0 100644
--- a/travo/dashboards.py
+++ b/travo/dashboards.py
@@ -43,7 +43,7 @@ import numpy as np    # type: ignore
 import pandas as pd   # type: ignore
 
 from .assignment import Assignment
-from .course import Course
+from .course import Course, CourseAssignment
 
 from .gitlab import GitLab, AuthenticationError, ResourceNotFoundError, unknown
 from .utils import run
@@ -478,8 +478,12 @@ class CourseStudentDashboard(VBox):
 
     def update_student_group(self) -> None:
         student_group = self.student_group_UI.value
-        for assignment in self.assignments:
-            self.assignment_dashboards[assignment].student_group = student_group
+        for assignment_name in self.assignments:
+            assignment_dashboard = self.assignment_dashboards[assignment_name]
+            assignment = assignment_dashboard.assignment
+            assert isinstance(assignment, CourseAssignment)
+            assignment.student_group = student_group
+            assignment_dashboard.update()
 
     def update(self, update_assignment_list: bool = False) -> None:
         student_group = self.student_group_UI.value