diff --git a/dune/tectonic/localnonlinearity.hh b/dune/tectonic/localnonlinearity.hh
index 838f7050ab2ce2033163e955b8f08ea5b0c399ba..339959ef1ff81153460b756e502503e329ebc1aa 100644
--- a/dune/tectonic/localnonlinearity.hh
+++ b/dune/tectonic/localnonlinearity.hh
@@ -89,7 +89,7 @@ template <int dimension> class LocalNonlinearity {
 
   void addGradient(VectorType const &x, VectorType &y) const {
     double const xnorm = x.two_norm();
-    if (xnorm < 1e-8 or std::isinf(func_->regularity(xnorm))) // TODO
+    if (xnorm == 0 or std::isinf(func_->regularity(xnorm)))
       return;
 
     // left and right differential coincide in this case