diff -r 258056f533ce -r b80b2fbc46c3 src/Pure/PIDE/document.scala
--- a/src/Pure/PIDE/document.scala	Thu Sep 22 16:29:26 2022 +0200
+++ b/src/Pure/PIDE/document.scala	Thu Sep 22 17:24:50 2022 +0200
@@ -333,7 +333,7 @@
     def command_start(cmd: Command): Option[Text.Offset] =
       Node.Commands.starts(commands.iterator).find(_._1 == cmd).map(_._2)
 
-    def source: String =
+    lazy val source: String =
       get_blob match {
         case Some(blob) => blob.source
         case None => command_iterator().map({ case (cmd, _) => cmd.source }).mkString
@@ -530,6 +530,15 @@
       node_name :: node.load_commands.flatMap(_.blobs_names)
 
 
+    /* source text */
+
+    def source: String =
+      snippet_command match {
+        case Some(command) => command.source
+        case None => node.source
+      }
+
+
     /* edits */
 
     def is_outdated: Boolean = edits.nonEmpty
@@ -1152,8 +1161,7 @@
         } yield tree).toList
       }
       else {
-        val node_source = node.source
-        Text.Range(0, node_source.length).try_restrict(range) match {
+        Text.Range(0, node.source.length).try_restrict(range) match {
           case None => Nil
           case Some(node_range) =>
             val markup =
@@ -1164,7 +1172,7 @@
                   val markup_index = Command.Markup_Index(false, chunk_name)
                   command_markup(version, command, markup_index, node_range, elements)
               }
-            markup.to_XML(node_range, node_source, elements)
+            markup.to_XML(node_range, node.source, elements)
         }
       }
     }