Hi
You need to write logic PBO
module output.
if sy-ucom = <button>.
loop at screen.
if screen-name = <feildname>.
screen-input = 1.
modify screen.
endif.
endloop.
endif.
endmodule.
otherwise you can mention all fields which you want to enable into one group and use like below
module output.
if sy-ucom = <button>.
loop at screen.
if screen-gruop1 = <groupname>.
screen-input = 1.
modify screen.
endif.
endloop.
endif.
endmodule.
regards.
laxman