- * If you are running XEmacs under the X Window System, a menu bar at
- the top of the frame makes shortcuts to several of the commands
- available (*note Pull-down Menus::).
+ * If you are running XEmacs under a graphical windowing system, a
+ menu bar at the top of the frame makes shortcuts to several of the
+ commands available (*note Pull-down Menus::).
+
+ * Under a graphical windowing system, a toolbar at the top of the
+ frame, just under the menu bar if it exists, provides "one-touch"
+ shortcuts to several commands. (Not yet documented.)
+
+ * Under a graphical windowing system, a gutter at the top (under the
+ toolbar) and/or bottom of the frame provides advanced GUI
+ facilities like tab controls for rapid switching among related
+ windows and progress bars for time-consuming operations like
+ downloads across the Internet. Gutters are an experimental feature
+ introduced in XEmacs version 21.2. (Not yet documented.)