The C1SplitButton control provides a context menu for additional resources at design time. Right-click on the C1SplitButton control to open its context menu. 

The C1Input context menu operates as follows:

About ComponentOne Input
Clicking the About ComponentOne Input link displays the About ComponentOne Input dialog box, which is helpful in finding the version number of the control and online resources.

Edit Items...

Clicking the Edit Items... opens the DropDownItem Collection Editor where you can add or remove dropdown items.