Hello Ben Hayat,
LoadDelay depends on a DispatcherTimer to operate. The DispatcherTimer (and Dispatcher) is something that pertains to the UI and Controls only. It is UI-specific.
Since the QDSCV is not a control, it has no Dispatcher associated and is not allowed to get involved in UI-specific stuff. It is not its job to decide when to load. Someone from the outside has to command the QDSCV and tell it when to load. In the default case this is the RadDomainDataSourceControl. In the case when the QDSCV is inside a custom view model -- it's up to you.
Since the QDSCV is always used inside a ViewModel, you can develop *any kind* of timing logic in the View by using Dispatchers and DispatcherTimers. When your logic *decides* that it is time for the QDSCV to load, you should simply call its Load method and instruct it to Load.
To learn more about how RadDomainDataSource does all these Dispatcher stuff, I suggest that you take a look at its source code.
I hope this helps.
the Telerik team