Selection-Screen - Warning for similar screens with same info

Question

Hi Gurus!
I have a small question regarding the screens. I have a program which splitting of the UWI's. This program has a selection screen  for entry of the company code , plant and date and two radiobuttons to show incomplete ones and all lists. Now the problem is that when this report is used by 3 or 4 people in the department and if they are working on the same plant say 0311, everyone has this screen opened and can make changes without the other person knowing that the other person is also doing changes . I want to make something in the repot that will give a message that this screen is already opened for this particular plant (warning message) which will make the other ppl aware that someone is already working on that plant , not only that evben if a single person has two screens of it opened with similar plant , also it should give message as that its opened for that particular plant. Is it possible please.?
So like in here in my report I should be adding in something or what?
*&                  Module  CHECK_INPUT  INPUT                         *
*                      Field Input Check                               *
MODULE check_input INPUT.
  DATA: lv_plant TYPE t001k-bukrs.
**** Checking For Plant Input.
  IF dyn_plant IS INITIAL.
    MESSAGE e000 WITH text-002.
  ELSE.
    SELECT SINGLE bwkey FROM t001k INTO t001k-bwkey
                  WHERE bwkey = dyn_plant.
    IF sy-subrc NE 0.
      MESSAGE e000 WITH text-019.
    ENDIF.
  ENDIF.
Thanks
Aarav

Answer 1

I used the enqueue and dequeue function module in my program to dis-allow two or more people to work on the same screen with similar input of plant ,and I am getting the error message too on the first screen itself that "selected plant si used by another user", but the problem is that its not allowing me to get into it even when I am the first user, I wanted actually it to happen with the second user or if I open up another screen and try inputing same plant and try entering then it should give me the message but its giving me message in the first screen itself and locking , not allowing me to get in.
Kindly suggest what should I be doing to this happen in the second or thisrd ascreen and so on , but not on the frist screen.
I put the logical lock after the plant validation happens , but for teh first user it should allowing him to go through the screen  and just give warning for other uses if they enter the same plant and try entering the screen.
Thanks
Aarav