A snapline's priority acts as a suggestion to visual designers about how to treat a snapline with respect to its peers. The layout engine uses a simple method of determining whether to display the snaplines for a control: only the highest priority snaplines, including those with a value of SnapLinePriority.Always, are shown for each orientation—vertical or horizontal.
To set the priority of a snapline, a System.Windows.Forms.Design.Behavior.SnapLinePriority enumeration is specified when creating an instance of the System.Windows.Forms.Design.Behavior.SnapLine class.