4D v15 introduces the form event On Scroll (renamed from On Picture Scroll in 4D v14.)

Here are a few things to note about this event:

1. The event is only available for picture variables and listboxes


2. The picture format must be truncated, and the picture must be smaller than the variable frame (so scrolling is possible.)


3. Listbox must have data in it, and must be scrollable.

The event can be triggered when:

1. The mouse hovers over object and wheel is scrolled.


2. The scroll bar up/down arrow is pressed.


3. The scroll bar is dragged (on begin drag.)

When the event is triggered, scroll position is changed first before event is fired off.