Todo: better summary
Focus the async textbox and write some text, leave it focussed
Click the async button, immediatly click the async link
Repeat 2. & 3., but with the link clicked first.
Observe that the button always is the second postback triggered
When is CheckFormState called?
Async Button Click:
Async Link Click:
Sequence Autopostback - Button - Link
Sequence Autopostback - Link - Button
Revision 6052 - 1.3.26 (Possibly longer)