Some debug hints what is happening
Tasks w/o descriptors are invisible by default.

So, make it visible in this test, as is needed to
have it back.
More backward compat stuff.

Cancellable status is required by IT. Also, task state handling
fixed
More consistent state handling

Now scheduled tasks were detected as "done" before they
really started (when they become started). Now the state is
more consistently handled, except for "done" detection
case that still suffers from some edge cases.