title: Get row ID when user double clicks the row in ALV report
body: <p>I have a scenario which displays a list of purchase documents as ALV (function module <code>REUSE_ALV_LIST_DISPLAY</code>). By clicking on a purchase doc no, its specific details (e.g. <code>NETPR</code>) should show in a pop up. How should I do it?</p>
  <pre><code>  FORM USER_COMMAND USING R_UCOMM LIKE SY-UCOMM
          RS_SELFIELD TYPE SLIS_SELFIELD.
      CASE r_ucomm.
        WHEN '&amp;IC1'.
  
          READ TABLE ITAB INTO WA WITH KEY EBELN = WA-EBELN.
          PERFORM popup_display.
  
      ENDCASE.
    ENDFORM.                    &quot;user_command
  </code></pre>