Tabs list is a drop-down functionality that can be shown on the caption area of the Docking Tab Page. For this purpose, the C1DockingTab class provides the ShowTabList property. On setting this property to true, a downward-pointing arrow appears on the caption. At runtime, when clicking the arrow, a dropdown menu appears with the list of all tabs.

You can set the ShowTabList property in the Properties window, or programmatically in the code editor:

dockingTab.ShowTabList = true;