diff --git a/src/components/DocumentView/CodeBlock/highlight.ts b/src/components/DocumentView/CodeBlock/highlight.ts
index 600afaa322..ad4138cabc 100644
--- a/src/components/DocumentView/CodeBlock/highlight.ts
+++ b/src/components/DocumentView/CodeBlock/highlight.ts
@@ -37,8 +37,6 @@ type PositionedToken = ThemedToken & { start: number; end: number };
 let blockCount = 0;
 const BLOCK_LIMIT = 50;
 
-const runner = asyncMutexFunction();
-
 /**
  * Highlight a code block while preserving inline elements.
  */