ToolControl is a non-creatable object. References to non-creatable objects must be obtained through other objects.
A ToolControl is a dropdown list box control, editable textbox control, or other type of control that can be added to a toolbar.
To create a custom ToolControl, implement both the esriSystemUI.ICommand and esriSystemUI.IToolControl interfaces.
Only one instance of a particular toolcontrol is allowed to exist in the application at one time.