diff --git a/backend/g_sheet/app.py b/backend/g_sheet/app.py
index b70074c..012698d 100644
--- a/backend/g_sheet/app.py
+++ b/backend/g_sheet/app.py
@@ -203,9 +203,6 @@ async def fetch_form_data(
     search: str | None = Query(None),
     processing_state: str | None = Query(None),
     is_duplicate: bool | None = Query(None),
-    # Tri-valued, like is_duplicate above: omit for no filter, true for rows that
-    # have the link, false for the ones missing it. Chasing the gaps is half the
-    # reason these exist, so `false` has to be a real filter and not "unset".
     has_linkedin: bool | None = Query(None),
     has_resume: bool | None = Query(None),
     city: str | None = Query(None),
@@ -213,7 +210,6 @@ async def fetch_form_data(
     assigned: bool | None = Query(None),
     no_suggestions: bool | None = Query(None),
     offset: int = Query(0,ge=0),
-    # Caller-chosen page size (Inbox sends 10/25/50/100). None = unpaged.
     limit: int | None = Query(None,ge=1,le=500),
     current_user: dict = Depends(_FORM_DATA_READ),
     session: AsyncSession = Depends(get_session),
diff --git a/frontend/src/screens/Inbox.jsx b/frontend/src/screens/Inbox.jsx
index 62e798a..09d52bc 100644
--- a/frontend/src/screens/Inbox.jsx
+++ b/frontend/src/screens/Inbox.jsx
@@ -68,6 +68,43 @@ const LIST_CACHE = {
 }
 const COUNT_CACHE = { staleTime: INBOX_STALE_MS, gcTime: INBOX_GC_MS }
 
+/**
+ * Last 10 opened applicant details. The queue list is a light row; GET-by-id
+ * is the body, suggested roles, resume text. Re-opening one of these should
+ * not pay that trip again. Cap is LRU — the 11th open drops the oldest from
+ * the query cache. Mutations that write THIS row still invalidate its key.
+ */
+const OPENED_DETAIL_CAP = 10
+const openedDetailLru = []
+
+function detailQueryKey(kind, id) {
+  return kind === 'form' ? qk.mailbox.formRow(id) : qk.mailbox.message(id)
+}
+
+function rememberOpenedDetail(qc, kind, id) {
+  if (!id) return
+  const sig = `${kind}:${id}`
+  const key = detailQueryKey(kind, id)
+  const next = openedDetailLru.filter((x) => x.sig !== sig)
+  next.push({ sig, kind, id, key })
+  while (next.length > OPENED_DETAIL_CAP) {
+    const dropped = next.shift()
+    if (dropped && dropped.sig !== sig) {
+      qc.removeQueries({ queryKey: dropped.key })
+    }
+  }
+  openedDetailLru.length = 0
+  openedDetailLru.push(...next)
+}
+
+const DETAIL_CACHE = {
+  staleTime: Infinity,
+  gcTime: INBOX_GC_MS,
+  refetchOnMount: false,
+  refetchOnWindowFocus: false,
+  refetchOnReconnect: false,
+}
+
 /** Typing must not put a query key (and a skeleton) on screen per keystroke. */
 const SEARCH_DEBOUNCE_MS = 300
 
@@ -1388,7 +1425,12 @@ export default function Inbox() {
     queryKey: selectedKind === 'form' ? qk.mailbox.formRow(selectedId) : qk.mailbox.message(selectedId),
     queryFn: () => (selectedKind === 'form' ? fetchFormDetail(selectedId) : fetchMessageDetail(selectedId)),
     enabled: Boolean(selectedId),
+    ...DETAIL_CACHE,
   })
+  useEffect(() => {
+    if (!selectedId || !detailQuery.isSuccess || !detailQuery.data) return
+    rememberOpenedDetail(qc, selectedKind, selectedId)
+  }, [qc, selectedId, selectedKind, detailQuery.isSuccess, detailQuery.data])
   // List rows paint immediately; GET-by-id is the full application. Block every
   // control in the detail pane until that fetch succeeds. The queue stays live.
   const detailLocked = Boolean(selectedId) && !detailQuery.isError && !detailQuery.isSuccess