diff --git a/helpers/Dojo/SharedAssignmentHelper.ts b/helpers/Dojo/SharedAssignmentHelper.ts
index 7c87bc2e47cedf713d4fef68a9d6749bc13e85a8..007f7bf29b2ae2525a3f4e2f785da5aff3579491 100644
--- a/helpers/Dojo/SharedAssignmentHelper.ts
+++ b/helpers/Dojo/SharedAssignmentHelper.ts
@@ -24,9 +24,11 @@ class SharedAssignmentHelper {
                 },
 
                 result: {
-                    properties: {
-                        container: { type: 'string' },
-                        volume   : { type: 'string' }
+                    properties        : {
+                        container: { type: 'string' }
+                    },
+                    optionalProperties: {
+                        volume: { type: 'string' }
                     }
                 }
             },