minor: getting rid of warning

SVN: 23017

openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/ParameterField.java

@@ -122,6 +122,7 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
         return new ParameterWithValue(parameterName, getRawValue());
     }
 
+    @Override
     public Field<?> asWidget()
     {
         return this;