diff --git a/frontend/tests/panel.spec.ts b/frontend/tests/panel.spec.ts
index 1f17c95..d2dcaf9 100644
--- a/frontend/tests/panel.spec.ts
+++ b/frontend/tests/panel.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import type { PanelDef } from "../src/client"
 import { api, apiPage, deleteAll } from "./utils/api"
 
 /**
@@ -16,6 +17,8 @@ import { api, apiPage, deleteAll } from "./utils/api"
 const flowName = `test_panel_${Date.now().toString(36)}`
 const first = `${flowName}_a`
 const second = `${flowName}_b`
+/** The installation's own panels, put back by the teardown. */
+let panels: PanelDef[] | null = null
 
 test.use({ storageState: "playwright/.auth/user.json" })
 test.describe.configure({ mode: "serial" })
@@ -69,16 +72,33 @@ test.beforeAll(async ({ browser }) => {
     })
   }
 
+  // Saving is a whole-list replace, and a panel that disappears takes the
+  // credential of the screen hanging on it. So append to what is there, and
+  // keep the list for the teardown to put back.
+  const config = await (await api(page, "/panels/")).json()
+  const existing: PanelDef[] = (config.panels ?? []).filter(
+    (p: PanelDef) => p.id !== flowName,
+  )
+  panels = existing
   await api(page, "/panels/", {
     method: "PUT",
     data: {
-      panels: [{ id: flowName, title: "Hall", dashboards: [first, second] }],
+      panels: [
+        ...existing,
+        { id: flowName, title: "Hall", dashboards: [first, second] },
+      ],
     },
   })
   await page.close()
 })
 
 test.afterAll(async ({ browser }) => {
+  // Restoring the list is also what removes this spec's own panel.
+  if (panels) {
+    const page = await apiPage(browser)
+    await api(page, "/panels/", { method: "PUT", data: { panels } })
+    await page.close()
+  }
   await deleteAll(browser, [
     `/dashboards/${first}`,
     `/dashboards/${second}`,