diff --git a/src/editor/core/cm/setup.ts b/src/editor/core/cm/setup.ts
index e029468c0..1c01eac6b 100644
--- a/src/editor/core/cm/setup.ts
+++ b/src/editor/core/cm/setup.ts
@@ -324,6 +324,13 @@ export interface SetupOptions {
  * below its top edge. WebKit positions them `absolute` within `.cm-editor`, so
  * a window-wide right bound makes CodeMirror skip the shift left and the
  * browser squeezes the box into the space left of the editor's edge.
+ *
+ * They are parented to the body (#2310): tooltips are `position: fixed` but
+ * appended inside the editor by default, whose `.content{isolation:isolate}`
+ * stacking context paints as one unit below the later bottom toolwindow — so
+ * completion popups got covered where they overflowed the editor's bottom
+ * edge. At the body level their z-index (500) sits above panels
+ * (`--z-panel: 10`) while staying below dialogs (`--z-dialog: 900`).
  */
 export function tooltipBounds(view: { scrollDOM: Element; dom: Element }) {
   const { top } = view.scrollDOM.getBoundingClientRect();
@@ -336,7 +343,10 @@ export function tooltipBounds(view: { scrollDOM: Element; dom: Element }) {
   };
 }
 
-const tooltipSpace = tooltips({ tooltipSpace: tooltipBounds });
+const tooltipSpace = tooltips({
+  parent: typeof document === "undefined" ? undefined : document.body,
+  tooltipSpace: tooltipBounds,
+});
 
 export function baseExtensions(o: SetupOptions): Extension {
   return [
diff --git a/src/editor/lsp/hoverPrecedence.test.ts b/src/editor/lsp/hoverPrecedence.test.ts
index 1c42150b8..5f36ea285 100644
--- a/src/editor/lsp/hoverPrecedence.test.ts
+++ b/src/editor/lsp/hoverPrecedence.test.ts
@@ -110,7 +110,8 @@ describe.each([
     view = editor();
     activateHover(view, 2, 1);
     await settle();
-    const tooltip = view.dom.querySelector(".cm-tooltip")!;
+    // Tooltips are parented to the body (#2310), not to the editor element.
+    const tooltip = document.querySelector(".cm-tooltip")!;
     tooltip.dispatchEvent(new MouseEvent("mousemove", { bubbles: true }));
     expect(pointerTarget()).toBe(tooltip);
     key("keydown", mod, { [flag]: true });