In the Properties window, split properties are accessed through the Splits property. By clicking on the ellipsis button (...) next to the Splits node, the editor for the Split Collection will appear. This editor can be used to access all of the split-specific properties as well as the C1DisplayColumnCollection properties for the current split. For more information on using the collection editor see Using the Split Collection Editor.
In addition, split-specific properties are available in the C1TrueDBGrid Designer. For more information see Using the C1TrueDBGrid Designer.