diff --git a/Modules/cell_base.f90 b/Modules/cell_base.f90
index aa4bdf200..7d0c0e5bf 100644
--- a/Modules/cell_base.f90
+++ b/Modules/cell_base.f90
@@ -635,6 +635,9 @@ END FUNCTION saw
               iforceh      = 0
               iforceh(1,1) = 1
               iforceh(2,2) = 1
+              ! ... if you want the entire xy plane to be free, uncomment:
+              ! iforceh(1,2) = 1
+              ! iforceh(2,1) = 1
             CASE ('xz')
               iforceh      = 0
               iforceh(1,1) = 1
diff --git a/PW/Doc/INPUT_PW.def b/PW/Doc/INPUT_PW.def
index 3e39453fd..8576044c6 100644
--- a/PW/Doc/INPUT_PW.def
+++ b/PW/Doc/INPUT_PW.def
@@ -1770,8 +1770,9 @@ input_description -distribution {Quantum Espresso} -package PWscf -program pw.x
                xyz     = only v1_x, v2_x, v_3z are moved
                shape   = all axis and angles, keeping the volume fixed
 
-               Beware: if axis are not orthogonal, some of the above options
-                       will break symmetry
+               BEWARE: if axis are not orthogonal, some of these options do not
+                work (symmetry is broken). If you are not happy with them, 
+                edit subroutine init_dofree in file Module/cell_base.f90
 	    }
 	}
     }