The scroll position property controls relocation of the viewport when the viewport is scrolled past the boundaries of the data view extent. This scroll position property forces relocation to the top of the data view, or causes it to remain in its previous location after adjustment to be inside the data view, if any. The scroll position property only applies to Cooperative Scrolling, also called Mode 2.
The position property controls the relocation of the viewport to ensure that the viewport always is placed within the data view boundaries. When the viewport is relocated to the top, or first row, of the data view, then the viewport origin is set to coincide with the first row of the data view. When the viewport is relocated to the end of the view, then the viewport origin is set such that the last row of the viewport is coincident with the last row of the data view boundaries. When the view is protected and the population does not equal or exceed the size of the viewport, then positioning to the end of the data view is ignored and the viewport is positioned to the beginning of the data view.
Relocation of the viewport depends upon the scroll positioning property specified by the user.
If scrolling is forward, then the NEXT common command is passed to the procedure step. If scrolling is backward, then the PREV common command is passed to the procedure step.
If a locate request is issued that positions the viewport outside of the data view boundaries, then it is treated the same as a NEXT common command that scrolled outside of the data view. The common command is set to NEXT.
If a Max scroll operation is requested, as well as a top or bottom request, then the viewport is positioned at the end of the data view boundaries appropriate for the request, and a NEXT or PREV common command is passed to the procedure step. The viewport is positioned at the beginning of the data view if the request was for TOP or Max backward, regardless of the positioning property. Likewise, if the command is BOTTOM or Max forward, then the positioning property determines the viewport relocation.
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