Refine poptoshell description slightly

diff --git a/README.md b/README.md
index 7ff703c1d1f64a3e79f99022a04cce07560706aa..c1d9555b70f736048e3f549a3416517a1dc66574 100644 (file)
--- a/README.md
+++ b/README.md
@@ -42,7 +42,8 @@ I've been using Emacs since it was publicly available (1985 or 1986), and have c
       completion is done against existing shell buffer names stripped of
       their asterisks.)
   * With a doubled universal arg, prompt for the target shell buffer and
-    use the provided name as the ensuing default.
+    use the provided name as the ensuing default. This is how the "primary"
+    is chosen.
 
   The last few things enable a kind of project-focus mode.  I often have
   various shell buffers, each one associated with a project. As I switch