How to select multiple ranges for a parameter WITHOUT first filling all other required parameters?

With parameters/select-options set to OBLIGATORY, this won't work. I had the very same problem some time ago, and had no chance to fill the OBLIGATORY input parameters with useful values by default, so I did the following:

• Remove the OBLIGATORY option from all select-options and parameters
• Handle the check for obligatory input yourself in cases no F4,help, F1 help or the button next to any select option is pressed:

Code:

AT SELECTION-SCREEN ON s_reswk.

IF sy-ucomm(1) <> '%' AND      " sel screen action request
   sy-ucomm(1) <> '_' AND      " scope option
   s_reswk IS INITIAL.         " Obligatory input missing
   MESSAGE text-e01 TYPE 'E'.  " Error message
ENDIF.