Returns or sets the percentage of the document window width that the outline pane occupies in normal view. Corresponds to the pane divider position between the slide and outline panes. Read/write Long.
Remarks
The maximum value of the SplitHorizontal property is always less than 100% because the slide pane has a minimum width that depends on a 10% zoom level. The actual maximum value may vary depending on the size of the application window.