Good question Steve.
When it comes to test automation, the general principle to follow is:
- The fewer the mouse operations the better
- The fewer the keyboard operations the better
In general, the fewer the UI operations you must perform the more reliable your test automation will be during execution. This isn't a hard and fast rule to follow (every application has it's unique way of operating)... only a recommended guideline.
For Silverlight we found that trying to inject click events was very unreliable in general. We wanted our customers to have the best chance of success that once they recorded their test, it would execute correctly and the test would pass. It was our experience that the using real mouse clicks for Silverlight applications was more reliable than trying to inject click events, even though this violates the "the fewer the mouse operations the better" rule to test automation.
This is why the default is different between HTML based applications and Silverlight based applications.
All the best,
the Telerik team