diff --git a/modules/gui/pymod/dng/superpositiondialog.py b/modules/gui/pymod/dng/superpositiondialog.py
index 2112ce2cd97e12fe828c53bd3d3e10be23c5ad26..fa6ae50fbb1ae77a96b3eae862efc4ec8feef337 100644
--- a/modules/gui/pymod/dng/superpositiondialog.py
+++ b/modules/gui/pymod/dng/superpositiondialog.py
@@ -220,7 +220,7 @@ class SuperpositionDialog(QDialog):
     view_one = self._chain_one.selected_chain
     view_two = self._chain_two.selected_chain
     atoms = self._GetAtomSelection()
-    sp = Superpose(view_one, view_two,
+    sp = Superpose(view_two, view_one,
                    self._mmethod_dict[str(self._methods.currentText())],
                    atoms)
     self.rmsd = sp.rmsd