-<li>if you wish to convert standard mesh to quadratic or quadratic to standard;</li>
-<li>if you wish to place medium nodes of the quadratic mesh on the geometry (meshed object).</li>
+<li>if it is necessary to convert a standard mesh to quadratic or a quadratic
+mesh to standard. Note that the choice is available only if the selected mesh
+(or sub-mesh) contains both quadratic and linear elements, else the
+direction of conversion is selected automatically.</li>
+
+<li>if it is necessary to place medium nodes of the quadratic mesh on the
+geometry (meshed object). This option is relevant for conversion to
+quadratic provided that the mesh is based on a geometry (not imported from file).</li>