You might have placed your ALV inside a TAB strip.. Hence clicking on the white space takes you to the top.. for some reason the focus is set to the TAB control.. I guess there is no solution for this at present but there is workaround.. You may need to remove your tab strip or break the pages so that your ALV data shows up on the first page always and not flows to the next page or you can put a tray container inside the TAB strip and then place your ALV container..
Let me know if this works.
Regards,
Senthil