TypeCellOS
diff --git a/‎packages/core/src/extensions/Placeholder/Placeholder.test.ts‎
Lines changed: 23 additions & 0 deletions b/‎packages/core/src/extensions/Placeholder/Placeholder.test.ts‎
Lines changed: 23 additions & 0 deletions
diff --git a/‎packages/core/src/extensions/Placeholder/Placeholder.ts‎
Lines changed: 3 additions & 5 deletions b/‎packages/core/src/extensions/Placeholder/Placeholder.ts‎
Lines changed: 3 additions & 5 deletions
@@ -0,0 +1,23 @@
+import { expect, it } from "vite-plus/test";
+
+import { BlockNoteEditor } from "../../editor/BlockNoteEditor.js";
+
+/**
+ * @vitest-environment jsdom
+ */
+
+it("does not throw on unmount when its style element was already removed", () => {
+  const editor = BlockNoteEditor.create();
+  editor.mount(document.createElement("div"));
+
+  const styleEl = [...document.head.querySelectorAll("style")].find((el) =>
+    (
+      el.sheet?.cssRules[0] as CSSStyleRule | undefined
+    )?.selectorText?.startsWith(".placeholder-selector-"),
+  );
+  expect(styleEl).toBeDefined();
+  // e.g. a router merging the next page's `<head>` into the current one
+  styleEl!.remove();
+
+  expect(() => editor.unmount()).not.toThrow();
+});
@@ -89,11 +89,9 @@ export const PlaceholderExtension = createExtension(
 
             return {
               destroy: () => {
-                if (view.root instanceof window.ShadowRoot) {
-                  view.root.removeChild(styleEl);
-                } else {
-                  view.root.head.removeChild(styleEl);
-                }
+                // `remove()` is a no-op if something else (e.g. a router
+                // merging `<head>`) already detached the element.
+                styleEl.remove();
               },
             };
           },