ALV Grid refresh not working properly

Hello,

I have an ALV Grid, for which I want to refresh the data display with a refresh button.

In the ProcessAfterInput, I´m refreshing my internal table, fill it again and call the method "refresh_table_display".

The problem is, sometimes it works fine, sometimes it does nothing. When I go out of the program and in again, it is always refreshed. Where is the problem here and what can I do?

Michael