.

anatomy/forms.py

@@ -122,11 +122,12 @@ class AnatomyQuestionForm(ModelForm):
         new_exams = self.cleaned_data["exams"]
 
         for exam in old_exams:
-            if exam in new_exams:
-                exam.exam_questions.add(instance)
-            else:
+            if exam not in new_exams:
                 exam.exam_questions.remove(instance)
 
+        for exam in new_exams:
+            exam.exam_questions.add(instance)
+
         self.save_m2m()
 
         return instance

longs/forms.py

@@ -227,24 +227,19 @@ class LongForm(ModelForm):
         }
 
     def save(self, commit=True):
-        # Get the unsaved Long instance
         instance = ModelForm.save(self, False)
-
-        # Prepare a 'save_m2m' method for the form,
-        old_save_m2m = self.save_m2m
-
-        def save_m2m():
-            old_save_m2m()
-            instance.exams.clear()
-            for exam in self.cleaned_data["exams"]:
-                # We need the id here
-                instance.exams.add(exam.pk)
-
-        self.save_m2m = save_m2m
-
-        # Do we need to save all changes now?
-        # if commit:
         instance.save()
+
+        old_exams = instance.exams.all()
+
+        new_exams = self.cleaned_data["exams"]
+
+        for exam in old_exams:
+            if exam not in new_exams:
+                exam.exam_questions.remove(instance)
+
+        for exam in new_exams:
+            exam.exam_questions.add(instance)
         self.save_m2m()
 
         return instance