diff --git a/packages/codemirror/slider.mjs b/packages/codemirror/slider.mjs
index 5c2dcdab..44875e25 100644
--- a/packages/codemirror/slider.mjs
+++ b/packages/codemirror/slider.mjs
@@ -1,3 +1,4 @@
+import { ref } from '@strudel.cycles/core';
 import { WidgetType, ViewPlugin, Decoration } from '@codemirror/view';
 import { StateEffect, StateField } from '@codemirror/state';