[LyX/master] Fix bug #11127.

[Richard Kimberly Heck]

commit 9f79ab99ed43026cd1dbdd707ec07e9a83bd95c2
Author: Richard Kimberly Heck <rikih...@lyx.org>
Date:   Fri Apr 27 20:13:07 2018 -0400

    Fix bug #11127.
---
 lib/layouts/stdinsets.inc |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/lib/layouts/stdinsets.inc b/lib/layouts/stdinsets.inc
index fc54ac8..f03b915 100644
--- a/lib/layouts/stdinsets.inc
+++ b/lib/layouts/stdinsets.inc
@@ -361,6 +361,7 @@ InsetLayout Listings
        KeepEmpty             true
        FreeSpacing           true
        ForceLTR              true
+       ForcePlain            true
        NeedCProtect          true
        RefPrefix             lst
        HTMLTag               pre