diff --git a/src/ui/panelChrome.radioOwnership.test.mjs b/src/ui/panelChrome.radioOwnership.test.mjs
new file mode 100644
index 000000000..c52a4888e
--- /dev/null
+++ b/src/ui/panelChrome.radioOwnership.test.mjs
@@ -0,0 +1,67 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { PanelChrome } from './panelChrome.js';
+
+function classList(initial = []) {
+  const values = new Set(initial);
+  return {
+    contains: (value) => values.has(value),
+    add: (...items) => items.forEach((item) => values.add(item)),
+    remove: (...items) => items.forEach((item) => values.delete(item)),
+    toggle(value, force) {
+      if (force === true) values.add(value);
+      else if (force === false) values.delete(value);
+      else if (values.has(value)) values.delete(value);
+      else values.add(value);
+      return values.has(value);
+    },
+  };
+}
+
+test('opening an already-open Context still closes a stale compact Radio disclosure', (t) => {
+  const priorDocument = globalThis.document;
+  const contextPanel = {
+    id: 'global-context-panel',
+    classList: classList(),
+  };
+  globalThis.document = {
+    documentElement: { dataset: { uiTheme: 'tactical' } },
+    getElementById(id) {
+      return id === 'global-context-panel' ? contextPanel : null;
+    },
+  };
+  t.after(() => {
+    globalThis.document = priorDocument;
+  });
+
+  const radioDock = { classList: classList(['disclosure-open']) };
+  const calls = [];
+  const owner = {
+    _contextRadioDock: radioDock,
+    _setRadioDisclosure(open) {
+      calls.push(open);
+      radioDock.classList.toggle('disclosure-open', open);
+    },
+    _leftPanelStack: null,
+    _rightPanelStack: null,
+    _panelLayout: {
+      _leftStackPreferredPanelId: null,
+      _rightStackPreferredPanelId: null,
+    },
+    _syncPanelCollapseButton() {},
+    _scheduleLeftPanelLayout() {},
+    _scheduleRightPanelLayout() {},
+    shareLinkManager: null,
+    cockpitView: null,
+  };
+
+  PanelChrome.prototype.setPanelCollapsed.call(
+    owner,
+    'global-context-panel',
+    false,
+  );
+
+  assert.deepEqual(calls, [false]);
+  assert.equal(radioDock.classList.contains('disclosure-open'), false);
+});