If you really want to make use of the "answered" feature you should allow the author of the question to mark a specific comment as "the right answer".

In this case - there is only one answer with a "chain" of comments.

So - I have no way to mark the specific comment that really answers the question.

Think about it.

Uri

Thanks John

I'm afraid that's not entirely correct.

%GSET existed until Cache 5. Then it was changed to %SYS.GSET.

I do see %GSET in our new 2016 installations, but it does Not function same as SYS.GSET.

For example - one could Do ^%GSET and Do ^%SYS.GSET, in the 2016 %GSET you can't do it, you must supply some parameters.

Thank you Eduard.
To answer your question (1) :
I posted my question for one of our developers who added such an index and found that the index wasn't created after rebuild.
So I thought the reason might be that an indexed property cannot be null valued, I didn't bother to ask what will be the use of such an index...
From your answer I understand that this is NOT the reason why the index was not created, so we'll have to look somewhere else...
Thanks,
Uri