Hide or Show selected references

In Endnote20 I lost the function to hide of show selected references. According to the Help it could be found under the Reference menu, but it is not there. 

(From the “References” menu, select “Show Selected References”.) 

Does anyone know where the function can be found in Endnote20? I would like to select some references and edited the references as one group with Change/Move/Copy fields.