ALV grid update issue

Hi experts,

please help me with writing ALV report for testing purpose:

When user push the button "Planetypes" the program call screen 0100 with table It_planetypes:

CALL METHOD r_alv_grid->set_table_for_first_display
    EXPORTING
      i_structure_name = 'SAPLANE'
     CHANGING
       it_outtab = it_planetypes.

when user double click on the table the program puts the table it_sflight in the same container of screen 0100

      CALL METHOD r_alv_grid->set_table_for_first_display
          EXPORTING
            i_structure_name = 'SFLIGHT'
           CHANGING
             it_outtab = it_sflight.
     

The problem is that when user push "Back" and then " Planetypes" again the program call screen 100 with table it_sflight (shold be it_planetypes). It looks like I missed statement to clear outtab but I am not sure. Could you please help me to fix this problem.

Regards, Maria