Index: Core/Plugins/src/Core.Plugins.Map/PropertyClasses/MapLineDataProperties.cs
===================================================================
diff -u -r54d2453c0bea232c1c507ef9996143e6af8e3a61 -rc73b8a46873513c166ddccb0a2138c7b3fa42d63
--- Core/Plugins/src/Core.Plugins.Map/PropertyClasses/MapLineDataProperties.cs	(.../MapLineDataProperties.cs)	(revision 54d2453c0bea232c1c507ef9996143e6af8e3a61)
+++ Core/Plugins/src/Core.Plugins.Map/PropertyClasses/MapLineDataProperties.cs	(.../MapLineDataProperties.cs)	(revision c73b8a46873513c166ddccb0a2138c7b3fa42d63)
@@ -138,7 +138,7 @@
             {
                 MapTheme<LineCategoryTheme> mapTheme = data.Theme;
                 return mapTheme != null
-                           ? mapTheme.CategoryThemes.Select(ct => new LineCategoryThemeProperties(ct, mapTheme.AttributeName, data)).ToArray()
+                           ? GetCategoryThemes(mapTheme)
                            : new LineCategoryThemeProperties[0];
             }
         }
@@ -171,5 +171,10 @@
 
             return base.DynamicReadonlyValidator(propertyName);
         }
+
+        private LineCategoryThemeProperties[] GetCategoryThemes(MapTheme<LineCategoryTheme> mapTheme)
+        {
+            return mapTheme.CategoryThemes.Select(ct => new LineCategoryThemeProperties(ct, mapTheme.AttributeName, data)).ToArray();
+        }
     }
 }
\ No newline at end of file