Attaching sources to living individuals

Some time in the past year, Family Tree was changed to allow us to attach sources to living individuals. However, we may only do so if that living individual is the focus of the Source Linker window. If a living person is not the focus of the window, a warning symbol is displayed with the message, "Sources may not be attached to living persons." Now, I think that warning is clearly wrong, because I am able to open a new Source Linker window with that living person as the focus, and attach the source record to that person without error.

Are you sure the bug isn't the other way around and it's allowing something that it shouldn't?

I believe that russelhltn is correct; Family Tree does NOT support attaching sources to living person records. The ability to do so is a bug.
A more appropriate forum for this discussion is: https://getsatisfaction.com/familysearch

My experience has shown me that I can attach sources to living people, although attached sources are hidden as long as they are identified as Living. If they are new to Family Tree, I can create a new record and attach the source to that record. If they already exist in Family Tree, I must change the Source Linker window to make that living person the focus of the search, and then attach the source record to them.

As long as that person is marked as Living, the sources that I have attached to that person are hidden from my view. When I open their Person view, I see "Sources 0" and "Sources are not available for living persons". The moment I mark them as deceased, or give them a death date, all sources I have previously attached to that person immediately become visible.

One concern I have, is that I thought sources could only be attached to one person. So if you attach them to your living person, no one else can attach them to theirs. That could cause a problem down the line.

If FS went to the trouble of creating a error message when attaching sources to living people, it seems like a deliberate policy - and so that's why I think you've discovered a bug. I suppose there could have been a policy change, but that strikes me as less likely.

The ability to attach sources to living people may have appeared around November 2013, when the ability to show photos and other memories for living people was added. See https://familysearch.org/blog/en/tag/living-people

More likely, it was added when the Private Spaces feature was added in 2014. See https://familysearch.org/blog/en/private-spaces/

Each Family Tree user now has a private space that allows them to manage their own private information. The information in that space can only be seen by the individual user and no one else. All living people, their relationships, and their data will be stored in that space. For example, I can view information about myself and my close living relatives that I have added to Family Tree in this private space but no one else can. Information that someone else has added about living people, their relationships, and their data will be stored in their own private space.