1 files changed, 2 insertions, 1 deletions

diff --git a/lispref/frames.texi b/lispref/frames.texi
index 0f243135cbb..617a2a1d05d 100644
--- a/lispref/frames.texi
+++ b/lispref/frames.texi
@@ -899,7 +899,8 @@ frame is redisplayed.
 @defvar frame-title-format
 This variable specifies how to compute a name for a frame when you have
 not explicitly specified one.  The variable's value is actually a mode
-line construct, just like @code{mode-line-format}.  @xref{Mode Line
+line construct, just like @code{mode-line-format}, except that the
+@samp{%c} and @samp{%l} constructs are ignored.  @xref{Mode Line
 Data}.
 @end defvar