You can use this function when you want the taskbar button to flash.
run FlashTray. PROCEDURE FlashTray : DEFINE VARIABLE pfwi AS MEMPTR NO-UNDO. DEFINE VARIABLE hwndParent AS INTEGER NO-UNDO. RUN GetParent (CURRENT-WINDOW:HWND, OUTPUT hwndParent). SET-SIZE (pfwi) = 20. PUT-LONG (pfwi, 1) = GET-SIZE(pfwi). PUT-LONG (pfwi, 5) = hwndParent. PUT-LONG (pfwi, 9) = 2. /* = FLASW_TRAY */ PUT-LONG (pfwi,13) = 3. /* number of times to blink */ PUT-LONG (pfwi,17) = 0. /* blink rate in msec, 0=use system default */ RUN FlashWindowEx ( pfwi ). SET-SIZE(pfwi) = 0. END PROCEDURE. PROCEDURE GetParent EXTERNAL "user32.dll" : DEFINE INPUT PARAMETER ipWindow AS LONG. DEFINE RETURN PARAMETER ipParent AS LONG. END PROCEDURE. PROCEDURE FlashWindowEx EXTERNAL "user32.dll": DEFINE INPUT PARAMETER ipWindow AS MEMPTR. END PROCEDURE.