quick fix

Author: vkarpov15

lib/document.js

@@ -3540,9 +3540,6 @@ Document.prototype.$__reset = function reset() {
  */
 
 Document.prototype.$__undoReset = function $__undoReset() {
-  if (this.$isSubdocument) {
-    return;
-  }
   if (this.$__.backup == null || this.$__.backup.activePaths == null) {
     return;
   }
@@ -3561,8 +3558,10 @@ Document.prototype.$__undoReset = function $__undoReset() {
     }
   }
 
-  for (const subdoc of this.$getAllSubdocs()) {
-    subdoc.$__undoReset();
+  if (!this.$isSubdocument) {
+    for (const subdoc of this.$getAllSubdocs()) {
+      subdoc.$__undoReset();
+    }
   }
 };