How to enable SAVE button in PO

Hi Experts,

I am trying to enable SAVE button in purchase order.

I have done the following things :

1.Save is showing as visible and enabled in component configuration.

2. Added the Save as PDO action type in SPRO -->Configure control actions on header level.

   Added the method ZSAVE to this and enabled the action using

   cs_data-action_enabled = abap_true with in the method.

I am not able to see the SAVE button.

Please advise if any process errors.