diff -r 7d1127ac2251 -r c42960228a81 src/Pure/General/symbol.scala
--- a/src/Pure/General/symbol.scala	Sat Oct 17 16:08:30 2015 +0200
+++ b/src/Pure/General/symbol.scala	Sun Oct 18 17:20:20 2015 +0200
@@ -521,7 +521,7 @@
   /* control symbols */
 
   def is_control(sym: Symbol): Boolean =
-    sym.startsWith("\\<^") || symbols.control_decoded.contains(sym)
+    (sym.startsWith("\\<^") && sym.endsWith(">")) || symbols.control_decoded.contains(sym)
 
   def is_controllable(sym: Symbol): Boolean =
     !is_blank(sym) && !is_control(sym) && !is_open(sym) && !is_close(sym) && !is_malformed(sym)