diff --git a/lib/linguist/vendor.yml b/lib/linguist/vendor.yml
index e9af74e6..e432af3c 100644
--- a/lib/linguist/vendor.yml
+++ b/lib/linguist/vendor.yml
@@ -122,7 +122,7 @@
 - (^|/)Chart\.js$
 
 # Codemirror
-- (^|/)[Cc]ode[Mm]irror/(lib|mode|theme|addon|keymap)
+- (^|/)[Cc]ode[Mm]irror/(lib|mode|theme|addon|keymap|demo)
 
 # SyntaxHighlighter - http://alexgorbatchev.com/
 - (^|/)shBrush([^.]*)\.js$