1 files changed, 24 insertions, 1 deletions
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/group-page.js b/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
index 6b9c82a..7d13260 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
@@ -96,6 +96,30 @@ function GroupPage({ groupId, group, token, username, userId, userPrefs,
   // every registered app when a node predates the setting (or hasn't answered
   // yet), so nothing disappears for an existing group.
   const [enabledApps, setEnabledApps] = useState(null);
+  // Declared here rather than beside the render, because the effect below
+  // depends on it and a `const` further down would be in its temporal dead
+  // zone — the hook-ordering trap this codebase has already paid for.
+  const apps = visibleApps(enabledApps);
+
+  // The landing tab is chosen before the node has said which applications this
+  // group has, and a preference is a preference — not a promise that the app
+  // exists here. Two ways to land on a tab that renders nothing at all, with no
+  // tab shown active and no way to tell what went wrong: the group has Chat
+  // disabled while 'chat' is the default, or the reader's preferred app is one
+  // this group does not run. The first app the group *does* offer is the
+  // answer to both.
+  //
+  // Also covers an operator disabling the app someone is currently looking at:
+  // `enabledApps` changes live over `apps_enabled`, and being moved to a
+  // working tab beats being left staring at an empty panel.
+  //
+  // Settings is exempt: it is not an application, it is never in `apps`, and
+  // the create-group wizard lands on it deliberately.
+  useEffect(() => {
+    if (tab === 'settings') return;
+    if (!apps.length || apps.some(a => a.key === tab)) return;
+    setTab(apps[0].key);
+  }, [enabledApps, tab]);
   // Reconcile interval / debounce currently in effect on the node — shown
   // to the operator in Settings, not enforced from here (indexer.py owns
   // that). Null until the handshake ack arrives.
@@ -532,7 +556,6 @@ function GroupPage({ groupId, group, token, username, userId, userPrefs,
     setPreviewEntry(entry);
   }, [entries, onPlayQueue, onStopMusic]);
 
-  const apps = visibleApps(enabledApps);
   const commonProps = {
     groupId, transportRef, gekRef, status, username,
     entries, nodeDirs, nodeRoots, setEntries, setNodeDirs, setNodeRoots, applyIndex,