Friction: Fix save and delete method.

src/Model/Friction/Friction.py

@@ -228,9 +228,10 @@ class Friction(SQLSubModel):
         ssi = self._status.scenario_id
 
         return (
-            self._begin_strickler._owner_scenario == ssi
-            # or self._end_strickler._owner_scenario == ssi
-            or super(Friction, self).must_be_saved()
+            self._begin_strickler is not None
+            and (self._begin_strickler._owner_scenario == ssi
+                 # or self._end_strickler._owner_scenario == ssi
+                 or super(Friction, self).must_be_saved())
         )
 
     def _db_save(self, execute, data=None):

src/Model/Tools/PamhyrListExt.py

@@ -171,7 +171,7 @@ class PamhyrModelList(SQLSubModel):
                 lambda x: x[1],
                 filter(
                     lambda x: x[0] in indexes,
-                    enumerate(self._lst)
+                    enumerate(self.lst)
                 )
             )
         )