Input screen field not greyed-out

Hello Abap experts,

I am using an user defined screen and on the screen of the function group I have removed the INPUT check on the element list of the input-output field concerned but on the transaction screen display the particular field is still open for input.

I have also generated and activated the screen and function group.

Could anybody shed light on what I could have missed to get this screen field greyed-out?

regards