BC: Fix command rows.

src/Model/BoundaryCondition/BoundaryCondition.py

@@ -582,6 +582,9 @@ class BoundaryCondition(SQLSubModel):
         self._data.index(bc)
 
     def get_i(self, index):
+        if len(self.data) == 0:
+            return None
+
         return self.data[index]
 
     def get_range(self, _range):