diff --git a/dune/tectonic/globalnonlinearity.hh b/dune/tectonic/globalnonlinearity.hh
index 631c6913dd353f19680a7f455b5207638f999376..260982a24dcd1daabb2605884265bc5d93ede3c0 100644
--- a/dune/tectonic/globalnonlinearity.hh
+++ b/dune/tectonic/globalnonlinearity.hh
@@ -53,7 +53,6 @@ class GlobalNonlinearity {
     for (size_t i = 0; i < u.size(); ++i) {
       Interval<double> D;
       auto const res = restriction(i);
-      // TODO: is the coordinate system the right one here?
       res->directionalSubDiff(u[i], v[i], D);
       subdifferential[0] += D[0];
       subdifferential[1] += D[1];
diff --git a/dune/tectonic/localnonlinearity.hh b/dune/tectonic/localnonlinearity.hh
index 4ba501e3031bf235f1aba49563c2584b479269a3..75eb2cd4b6dab5c07d84f7b64a64c725012e45e2 100644
--- a/dune/tectonic/localnonlinearity.hh
+++ b/dune/tectonic/localnonlinearity.hh
@@ -43,7 +43,6 @@ template <int dimension> class LocalNonlinearity {
     }
     double const un = u.two_norm();
     double const ndotp = (u * v) / un;
-    // Our coordinate system is now such that v is a unit vector!
     if (ndotp > 0) {
       D[1] = ndotp * func_->rightDifferential(un);
       D[0] = ndotp * func_->leftDifferential(un);
diff --git a/src/TODO.org b/src/TODO.org
index 776476a65c7c4ef98e1f42af6c98d9a59405b529..5e66a10c35dcc8e5617db7885bd3c16af2a0a631 100644
--- a/src/TODO.org
+++ b/src/TODO.org
@@ -1,4 +1,3 @@
 * check if v should be normalised by default
-* the subdifferentials for the nonlinearity are probably taken w.r.t a different coordinate system
 * use nested iteration to obtain better iteration to start with
 * fix up octave bindings (low-pri)