ALV Not Refreshing Data

Hellow freinds,

I am also have same issue i make one GUI status , the process of screen as follow

Screen 100 -

> this User Slection screen, Here user start to make input and one Push button 'Display" when user click this Display the Programme Goes to Screen--101

Screen 101------> this is the result screen here ALV grid Display shows the result,

Now user click the Back Button (Standard Tool Bar) , then he see the first screen means screen 100 (Input screen)

Now user changes the value and again click Display for result ,so the problem is User can not see the correct result after pressing back , ALV shows the old result below is my code where i exporting the filed catalog.

 PERFORM get_fieldcatalog.

  CALL METHOD alv_grid->set_table_for_first_display
    EXPORTING
      is_layout        = layout
      is_variant       = variant
      i_save           = 'U'
      i_structure_name = 'I_ALV2'

    CHANGING

      it_outtab        = i_alv2[]
      it_fieldcatalog  = fieldcat[].

Plz give me some suggestion how to solve this issue.