Add a comment to clarify that calling setReactionFieldDielectric on force

instead of gb is intentional.

wrappers/python/simtk/openmm/app/internal/amber_file_parser.py

@@ -829,6 +829,8 @@ def readAmberSystem(prmtop_filename=None, prmtop_loader=None, shake=None, gbmode
             gb.setCutoffDistance(nonbondedCutoff)
         else:
             raise Exception("Illegal nonbonded method for use with GBSA")
+        # This applies the reaction field dielectric to the NonbondedForce
+        # created above. Do not bind force to another name before this!
         force.setReactionFieldDielectric(1.0)
 
     # TODO: Add GBVI terms?