If your application is an in-process component (ActiveX DLL) or an ActiveX control, the client
application will control the creation and management of threads. You may still, however, specify whether
your component will allow a single thread or multiple apartment threads.
You can specify whether your component supports multiple apartment threading by choosing either
Apartment Threaded or Single Threaded from the drop-down box in the Threading Model section under
the General tab of the Project, Properties dialog box, as shown in Figure 12.6.
Note that the default setting for in-process and control components is Apartment Threaded.
Finally, you can check the Unattended Execution box on the General tab of the Project, Properties
dialog box (refer again to Figure 12.6) to ensure that your in-process component is thread-safe.
FIGURE 12.6 Specifying the threading model for an inprocess component (ActiveX
DLL) or an ActiveX control.