That is interesting. I hadn't noticed that option before.
There is one hiccup with this feature. It only picks up individual persons in this file without a spouse, parents, or children.
It won't pick up anyone in an unattached branch.
For example, I am doing a surname study, for, let's say, Smith.
I have perheps 50 or more "master" unattached parents for people I can't place in categories, such as:
Unattached Alaska Smith
Unattached Alabama Smith
Unattached Civil War Records Smith
I then attach people that I have run across that I cannot attach to the master tree that I am following. Sometimes they are a true, separate line from a totally different immigrant than my "master" group. Sometimes I just can't place them yet. I will enter their parents, spouses, children, in-laws, etc, as I run across them. Nobody in that "chain" of people will be "caught" in the above list of unattached people in the Errors Report.
So, I use a filter for "unattached" to catch the 50 or so master Unattached categories - but have to look to see spouses, parents and children, and in-laws, if entered.