Improve documentation of `ns-use-proxy-icon`

* doc/emacs/macos.texi (Mac / GNUstep Customization):
* src/nsfns.m (syms_of_nsfns): Fix documentation of
'ns-use-proxy-icon'; explain what it does and how it's
used.  (Bug#66190)

2 files changed, 10 insertions, 2 deletions

diff --git a/doc/emacs/macos.texi b/doc/emacs/macos.texi
index 18811291a9e..8ace8ae7b2a 100644
--- a/doc/emacs/macos.texi
+++ b/doc/emacs/macos.texi
@@ -149,7 +149,10 @@ the corresponding left-hand key.
 @vindex ns-use-proxy-icon
 @item ns-use-proxy-icon
 This variable specifies whether to display the proxy icon in the
-titlebar.
+titlebar.  The proxy icon can be used to drag the file associated with
+the current buffer to other applications, much in the same way you
+would do it from Finder.  You might have to disable
+@code{tool-bar-mode} to see the proxy icon.
 
 @vindex ns-confirm-quit
 @item ns-confirm-quit
diff --git a/src/nsfns.m b/src/nsfns.m
index 5ae2cc77bb2..1aab5a3b508 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -3919,7 +3919,12 @@ be used as the image of the icon representing the frame.  */);
 
   DEFVAR_BOOL ("ns-use-proxy-icon", ns_use_proxy_icon,
                doc: /* When non-nil display a proxy icon in the titlebar.
-Default is t.  */);
+The proxy icon can be used to drag the file associated with the
+current buffer to other applications, much in the same way you would
+do it from Finder.  Note that you might have to disable
+`tool-bar-mode' to see the proxy icon.
+
+The default value is t.  */);
   ns_use_proxy_icon = true;
 
   DEFVAR_LISP ("x-max-tooltip-size", Vx_max_tooltip_size,