Improve documentation of 'w32-scroll-lock-modifier'

* doc/emacs/msdos.texi (Windows Keyboard): Document how to set up
w32-scroll-lock-modifier so that Scroll Lock toggles the LED.

* src/w32fns.c (syms_of_w32fns) <w32-scroll-lock-modifier>: Doc
fix.  (Bug#25204)

2 files changed, 7 insertions, 2 deletions

diff --git a/doc/emacs/msdos.texi b/doc/emacs/msdos.texi
index 47ba23b95aa..d0e9ab45c25 100644
--- a/doc/emacs/msdos.texi
+++ b/doc/emacs/msdos.texi
@@ -580,7 +580,11 @@ variable @code{w32-rwindow-modifier} controls the effect of the right
 Windows key, and @code{w32-scroll-lock-modifier} does the same for the
 @key{ScrLock} key.  If these variables are set to @code{nil}, the
 right Windows key produces the symbol @code{rwindow} and @key{ScrLock}
-produces the symbol @code{scroll}.
+produces the symbol @code{scroll}.  If you want @key{ScrLock} to
+produce the same effect as in other applications, i.e.@: toggle the
+Scroll Lock @acronym{LED} indication on the keyboard, set
+@code{w32-scroll-lock-modifier} to @code{t} or any non-@code{nil}
+value other than the above modifier symbols.
 
 @vindex w32-pass-alt-to-system
 @cindex Windows system menu
diff --git a/src/w32fns.c b/src/w32fns.c
index 27c0d65fbd0..9f4232d5b92 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -9425,7 +9425,8 @@ Set to nil to handle Caps Lock as the `capslock' key.  */);
 	       doc: /* Modifier to use for the Scroll Lock ON state.
 The value can be hyper, super, meta, alt, control or shift for the
 respective modifier, or nil to handle Scroll Lock as the `scroll' key.
-Any other value will cause the Scroll Lock key to be ignored.  */);
+Any other value will cause the Scroll Lock key to be ignored by Emacs,
+and it will have the same effect as in other applications.  */);
   Vw32_scroll_lock_modifier = Qnil;
 
   DEFVAR_LISP ("w32-lwindow-modifier",