diff --git a/src/hooks/useEngineConnectionSubscriptions.ts b/src/hooks/useEngineConnectionSubscriptions.ts
index ef5cb3459..e5411d39e 100644
--- a/src/hooks/useEngineConnectionSubscriptions.ts
+++ b/src/hooks/useEngineConnectionSubscriptions.ts
@@ -60,7 +60,8 @@ export function useEngineConnectionSubscriptions() {
           }
         } else if (
           !editorManager.highlightRange ||
-          (editorManager.highlightRange[0][0] !== 0 &&
+          (editorManager.highlightRange[0] &&
+            editorManager.highlightRange[0][0] !== 0 &&
             editorManager.highlightRange[0][1] !== 0)
         ) {
           editorManager.setHighlightRange([defaultSourceRange()])