src/Pure/PIDE/markup.scala

--- a/src/Pure/PIDE/markup.scala	Sat May 26 22:12:18 2018 +0100
+++ b/src/Pure/PIDE/markup.scala	Sun May 27 13:42:01 2018 +0200
@@ -242,6 +242,8 @@
 
   val HIDDEN = "hidden"
 
+  val DELETE = "delete"
+
 
   /* misc entities */