Redmine

In configuration of redmine I have chosen in the list box "Allow cross-project child issues" the feature
"With all projects".

Now I have two projects, which are not in same project tree. Let us denote project A and project B.
Both are independent from each other.
In project A I have a ticket 1 in tracker A.
In ticket 1 I create a child ticket and choose it to project B with tracker B. The child ticket is created in tracker B, project B correctly.
But the child ticket is not listed in ticket 1. The dependency is not shown.
I think that this is a bug.

The ticket will be shown, if project A and B has a mother project C.
If this is intended, then the option "With all project" in list box "Allow cross-project child issues" doesn't make sense and is obsolete.
Thanks and Best Regards
Stefan