You can access ActiveX controls in two modes:

Design-mode (or design-time) access allows you to modify properties that initialize the control and define it for use in an application. For many controls, these properties affect such attributes as color and size, but also enable and disable other special features unique to each ActiveX control. In general, design-time properties affect the appearance and initial internal state of an ActiveX control. Design-time properties are generally readable, but might not be writable at runtime.

Run-mode (or runtime) access allows your application to interact with the control, responding to events, invoking methods, and getting and setting properties that affect the ActiveX control at runtime. Run-time properties might not be readable or writable at design time.

The requirements for working in each mode differ.