diff --git a/formats/formula.js b/formats/formula.js
index 2e603c8137..606d8b1be7 100644
--- a/formats/formula.js
+++ b/formats/formula.js
@@ -8,13 +8,16 @@ class Formula extends Embed {
       katex.render(value, node);
       node.dataset.value = value;
     }
-    node.setAttribute('contenteditable', false);
     return node;
   }
 
   static value(domNode) {
     return domNode.dataset.value;
   }
+
+  index(node, offset) {
+    return 1;
+  }
 }
 Formula.blotName = 'formula';
 Formula.className = 'ql-formula';