ContainerProperties.ListAlignment Property (Visio)
Specifies how to align and arrange a list shape that you want positioned perpendicular to the main list direction. Read/write.
Use the ListAlignment property to position shapes along the axis that is perpendicular to the primary list direction. For example, if the primary list direction is horizontal in a given list container, you can use the ListAlignment property to align a shape vertically in that container. The value of the ListAlignment property can be one of the following VisListAlignment constants.
Left-align or top-align shapes.
Center-align or middle-align shapes.
Right-align or bottom-align shapes.
If the container is not a list, Microsoft Visio returns an Invalid Source error.