diff --git a/web/packages/core/src/register-element.ts b/web/packages/core/src/register-element.ts
index 3aca9e1bb..1132b91ec 100644
--- a/web/packages/core/src/register-element.ts
+++ b/web/packages/core/src/register-element.ts
@@ -1,3 +1,8 @@
+/**
+ * Number of times to try defining a custom element.
+ */
+const MAX_TRIES = 999;
+
 /**
  * A mapping between internal element IDs and DOM element IDs.
  */
@@ -70,7 +75,7 @@ export function registerElement(
 
     let tries = 0;
 
-    while (true) {
+    while (tries < MAX_TRIES) {
         let externalName = elementName;
         if (tries > 0) {
             externalName = externalName + "-" + tries;
@@ -96,4 +101,6 @@ export function registerElement(
 
         return externalName;
     }
+
+    throw new Error("Failed to assign custom element " + elementName);
 }