fix cant undo matching

editors/demo/src/HHMI/HHMI.js

@@ -167,7 +167,7 @@ const Hhmi = () => {
         ref={editorRef}
         customValues={{ showFeedBack: submitted, testMode }}
         fileUpload={file => renderImage(file)}
-        value={content}
+        // value={content}
         readonly={readOnly}
         layout={HhmiLayout}
         // onChange={source => console.log(source)}

wax-prosemirror-services/src/MatchingService/MatchingContainerNodeView.js

@@ -22,6 +22,13 @@ export default class MatchingContainerNodeView extends QuestionsNodeView {
     return 'matching_container';
   }
 
+  update(node) {
+    if (node.type.name === 'paragraph') {
+      if (!node.sameMarkup(this.node)) return false;
+    }
+    return super.update(node);
+  }
+
   stopEvent(event) {
     if (event.target.type === 'text') {
       return true;

wax-prosemirror-services/src/MatchingService/MatchingQuestion.js

@@ -16,7 +16,7 @@ class MatchingQuestion extends Tools {
     return main => {
       const { dispatch } = main;
       const { state } = main;
-      helpers.checkifEmpty(main);
+      // helpers.checkifEmpty(main);
       /* Create Wrapping */
       const { $from, $to } = main.state.selection;
       const range = $from.blockRange($to);