The grid widget has some undocumented trigger named VScrollBar_HitEnd that is supposed to get fired when the user scrolls down to the end. We would need this trigger to be officially supported and have the following limitation removed: the trigger only gets fired when the grid has the focus (as it is possible to scroll through a grid while the focus stays on another field or form).
We need this to implement a stepped hitlist in a dummy entity. Occurrences are retrieved in a separate service and when the user scrolls down to the end we need to retrieve the next occurrences. Currently this is not possible as we cannot detect and react on this condition. In fact this is exactly why that trigger has been introduced in the first place. From Uniface support: The Grid Extended Trigger VScrollBar_HitEnd has been specifically created for the IDF Open Form form in Uniface 9. Since this specific form is using a dummy entity our developers needed a mechanism to catch the event when the scroll bar reaches the bottom or the user is going to the last occurrence. When the mentioned event is occurring then the above mentioned trigger is fired and this will allow the 4GL developer to retrieve additional occurrences that can be added to the \\\\\\\"hit list\\\\\\\" of the Open Form form.