The lScrollInc parameter indicates a change in position. If the lScrollInc parameter value is greater than 0, the window specified in the usWindow parameter is scrolled to the right by the number of pixels specified in the lScrollInc parameter. If the value of the lScrollInc parameter is less than 0, the window specified in the usWindow parameter is scrolled to the left by the number of pixels specified in the lScrollInc parameter. This message is used to scroll either the left or right split window by an absolute amount.

The columns that are to appear in each split window are determined at the time the split window is created. Thereafter, columns in the left split window cannot be seen in the right split window, and vice versa.