How to Fix columns while using changing layout option in ALV Grid?

Hi,

I am using cl_gui_alv_grid class for displaying ALV Grid. My requirement is to fix the first 4 columns i.e. user should not be able to re-arrange the columns sequence, when change layout function is pressed.

Though I am passing the following values to field catalog, columns are not getting fixed. Only while horizontal scrolling the columns are fixed.

KEY = 'X'.

FIX_COLUMN = 'X'

Could you please let me know, if I have to fill any other fields in fieldcatalog ?

Thanks,

Savitha