Called by the framework to notify the item that it has just been activated in place.
Note that this function is called to indicate that the server is running, not to indicate that its user interface has been installed in the container application. At this point, the object does not have an active user interface (is not activeUIState). It has not installed its menus or toolbar. The OnActivateUI member function is called when that happens.
The default implementation calls the OnChange member function with OLE_CHANGEDSTATE as a parameter. Override this function to perform custom processing when an item becomes in-place active.