diff --git a/man7/cgroups.7 b/man7/cgroups.7
index c07160a09..1d7edd6e5 100644
--- a/man7/cgroups.7
+++ b/man7/cgroups.7
@@ -915,6 +915,12 @@ the delegater might instead add selected controllers to this file.)
 Changing the ownership of this file is necessary if a threaded subtree
 is being delegated (see the description of "thread mode", below).
 This permits the delegatee to write thread IDs to the file.
+(The ownership of this file can also be changed when delegating
+a domain subtree, but currently this serves no purpose,
+since, as described below, it is not possible to move a thread between
+domain cgroups by writing its thread ID to the
+.IR cgroup.tasks
+file.)
 .PP
 The delegater should
 .I not