diff --git a/src/toolbars/PreviewerBubble.js b/src/toolbars/PreviewerBubble.js
index 75242380..93da69b8 100644
--- a/src/toolbars/PreviewerBubble.js
+++ b/src/toolbars/PreviewerBubble.js
@@ -347,6 +347,9 @@ export default class PreviewerBubble {
   }
 
   $getClosestNode(node, targetNodeName) {
+    if (!node || !node.tagName) {
+      return false;
+    }
     if (node.tagName === targetNodeName) {
       return node;
     }
diff --git a/src/toolbars/Toc.js b/src/toolbars/Toc.js
index f6237bfc..c4d86c83 100644
--- a/src/toolbars/Toc.js
+++ b/src/toolbars/Toc.js
@@ -175,6 +175,9 @@ export default class Toc {
   }
 
   $getClosestNode(node, targetNodeName) {
+    if (!node || !node.tagName) {
+      return false;
+    }
     if (node.tagName === targetNodeName) {
       return node;
     }
diff --git a/src/utils/tableContentHandler.js b/src/utils/tableContentHandler.js
index d001618d..232d846c 100644
--- a/src/utils/tableContentHandler.js
+++ b/src/utils/tableContentHandler.js
@@ -370,6 +370,9 @@ export default class TableHandler {
   }
 
   $getClosestNode(node, targetNodeName) {
+    if (!node || !node.tagName) {
+      return false;
+    }
     if (node.tagName === targetNodeName) {
       return node;
     }