Alt-i, on Windows and Linux, and Control-Option-i on OSX (assuming you are
using the default keybindings).
+A change to how math macros are output can break some documents that use
+ERT to comment out macros. Please see bug #11216 if you experience this sort
+of problem.
+
If you think you have found a bug in LyX 2.3.1, please open a bug report at
http://www.lyx.org/trac/wiki/BugTrackerHome. If you're not sure whether it
really is a bug, you can e-mail the LyX developers' mailing list (lyx-devel
+!Important Change in LyX 2.3.1
+
+* A change to how math macros are output can break some documents that use
+ ERT to comment out macros. Please see bug #11216 if you experience this
+ sort of problem.
+
+
!Important Changes in LyX 2.3.0