diff --git a/nifty5/operators/mask_operator.py b/nifty5/operators/mask_operator.py
index ef61ac2502f8b53e8bd411eefce6a059f2743551..87407ee9a4bf4a44ab517c04a15ceca867aacc77 100644
--- a/nifty5/operators/mask_operator.py
+++ b/nifty5/operators/mask_operator.py
@@ -24,6 +24,9 @@ from ..field import Field
 from .linear_operator import LinearOperator
 
 
+# MR FIXME: this needs a redesign to avoid most _global_data() calls
+# Possible approach: keep everything living on `domain` distributed and only
+# collect the unstructured Fields.
 class MaskOperator(LinearOperator):
     def __init__(self, mask):
         if not isinstance(mask, Field):
diff --git a/nifty5/operators/slope_operator.py b/nifty5/operators/slope_operator.py
index cbeefb3a6081bd701f6576d6a641c49424120523..4e2f851c42c53d291e359d0cfe90ed478a1fd551 100644
--- a/nifty5/operators/slope_operator.py
+++ b/nifty5/operators/slope_operator.py
@@ -25,9 +25,8 @@ class SlopeOperator(LinearOperator):
                 rng = np.arange(target.shape[i])
                 tmp = np.minimum(
                     rng, target.shape[i] + 1 - rng) * target.bindistances[i]
-                fst_dims = (1,) * i
-                lst_dims = (1,) * (self.ndim - i - 1)
-                self.pos[i] += tmp.reshape(fst_dims + (shape[i],) + lst_dims)
+                self.pos[i] += tmp.reshape(
+                    (1,)*i + (shape[i],) + (1,)*(self.ndim-i-1))
 
     @property
     def domain(self):