diff --git a/hgext/highlight/highlight.py b/hgext/highlight/highlight.py
--- a/hgext/highlight/highlight.py
+++ b/hgext/highlight/highlight.py
@@ -22,8 +22,12 @@
     import pygments
     import pygments.formatters
     import pygments.lexers
+    import pygments.plugin
     import pygments.util
 
+    for unused in pygments.plugin.find_plugin_lexers():
+        pass
+
 highlight = pygments.highlight
 ClassNotFound = pygments.util.ClassNotFound
 guess_lexer = pygments.lexers.guess_lexer