ENH: regionProperties: added comment

src/regionModels/regionModel/regionProperties/regionProperties.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2012 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,7 +25,11 @@ Class
     regionProperties
 
 Description
-    Simple class to hold region information for coupled region simulations
+    Simple class to hold region information for coupled region simulations.
+
+    Gives per physics ('fluid', 'solid') the names of the regions. There
+    is no assumption on this level that one region should only have one
+    set of physics.
 
 SourceFiles
     regionProperties.C