If the panes are frozen, xSplit represents the number of columns visible in the top right pane. If the panes are not frozen, xSplit represents the position of the split, in 1/20th of a point, 0 (zero) if none.
ySplit
If the panes are frozen, ySplit represents the number of rows visible in the top right pane. If the panes are not frozen, ySplit represents the position of the split, in 1/20th of a point, 0 (zero) if none.