Improve documentation of secondary selections

* doc/emacs/killing.texi (Secondary Selection): Improve
wording.  Mention that 'M-mouse-1' can be used to cancel
secondary selections.  (Bug#36365)

1 files changed, 10 insertions, 6 deletions

diff --git a/doc/emacs/killing.texi b/doc/emacs/killing.texi
index 9b9c890331e..670decd67bd 100644
--- a/doc/emacs/killing.texi
+++ b/doc/emacs/killing.texi
@@ -605,16 +605,20 @@ This command does not alter the kill ring.
 @kindex M-mouse-1
 @item M-mouse-1
 Set one endpoint for the @dfn{secondary selection}
-(@code{mouse-start-secondary}).
+(@code{mouse-start-secondary}).  Use @kbd{M-mouse-3} to set the other
+end and complete the selection.  This command can also cancel any
+existing secondary selection without starting a new one, if you click
+@kbd{M-mouse-1} on the mode line or on the header line.
 
 @findex mouse-secondary-save-then-kill
 @kindex M-mouse-3
 @item M-mouse-3
-Set the secondary selection, with one end at the position clicked and
-the other at the position specified with @kbd{M-mouse-1}
-(@code{mouse-secondary-save-then-kill}).  This also puts the selected
-text in the kill ring.  A second @kbd{M-mouse-3} at the same place
-kills the secondary selection just made.
+Set the secondary selection (@code{mouse-secondary-save-then-kill}),
+with one end at the position you click @kbd{M-mouse-3}, and the other
+at the position specified previously with @kbd{M-mouse-1}.  This also
+puts the selected text in the kill ring.  A second @kbd{M-mouse-3} at
+the same place kills the text selected by the secondary selection just
+made.
 
 @findex mouse-yank-secondary
 @kindex M-mouse-2