diff --git a/SW.Bitween.Web/ClientApp/src/components/ui/SearchSelect.tsx b/SW.Bitween.Web/ClientApp/src/components/ui/SearchSelect.tsx
index 9e2b595f..e71d14c7 100644
--- a/SW.Bitween.Web/ClientApp/src/components/ui/SearchSelect.tsx
+++ b/SW.Bitween.Web/ClientApp/src/components/ui/SearchSelect.tsx
@@ -9,6 +9,13 @@ export interface SearchSelectOption {
   code?: string;
   /** Muted right-aligned text on the option row. */
   hint?: string;
+  /**
+   * Muted second line under the label, for context too long to sit beside it. Search matches
+   * it as well, since it is text the reader can see on the row.
+   */
+  sublabel?: string;
+  /** Native tooltip on the option row, for detail that would crowd it (a path, an id…). */
+  title?: string;
   /** Fully custom option row; label/code/hint rendering is skipped. */
   render?: ReactNode;
 }
@@ -64,7 +71,10 @@ export function SearchSelect({
     const needle = query.trim().toLowerCase();
     if (!needle) return all;
     return all.filter(
-      (o) => o.label.toLowerCase().includes(needle) || o.code?.toLowerCase().includes(needle),
+      (o) =>
+        o.label.toLowerCase().includes(needle) ||
+        o.code?.toLowerCase().includes(needle) ||
+        o.sublabel?.toLowerCase().includes(needle),
     );
   }, [all, query]);
 
@@ -97,29 +107,42 @@ export function SearchSelect({
           <ChevronsUpDown className="size-3.5" aria-hidden />
         </ComboboxButton>
       </div>
+      {/* The panel starts at the input's width but is free to outgrow it: several of these sit
+          in narrow filter bars, and an option is worth nothing if its name is the part that
+          gets truncated away. */}
       <ComboboxOptions
         anchor={{ to: "bottom start", gap: 4 }}
-        className="z-50 max-h-64 w-(--input-width) overflow-auto rounded-lg border border-ink-200 bg-white py-1 shadow-lg empty:hidden"
+        className="z-50 max-h-64 max-w-[min(28rem,90vw)] min-w-(--input-width) overflow-auto rounded-lg border border-ink-200 bg-white py-1 shadow-lg empty:hidden"
       >
         {filtered.map((o) => (
           <ComboboxOption
             key={o.value || "∅"}
             value={o.value}
+            title={o.title}
             className="group flex cursor-pointer items-center gap-2 px-3 py-1.5 data-focus:bg-ink-50"
           >
             {o.render ?? (
               <>
-                <span
-                  className={`min-w-0 flex-1 truncate text-sm ${o.value === "" ? "text-ink-500 italic" : "text-ink-800"}`}
-                >
-                  {o.label}
+                <span className="min-w-0 flex-1">
+                  <span
+                    className={`block truncate text-sm ${o.value === "" ? "text-ink-500 italic" : "text-ink-800"}`}
+                  >
+                    {o.label}
+                  </span>
+                  {o.sublabel && (
+                    <span className="block truncate text-xs text-ink-400">{o.sublabel}</span>
+                  )}
                 </span>
                 {o.code && (
                   <code className="shrink-0 rounded bg-ink-100 px-1.5 py-0.5 font-mono text-[11px] text-ink-600">
                     {o.code}
                   </code>
                 )}
-                {o.hint && <span className="shrink-0 text-xs text-ink-400">{o.hint}</span>}
+                {/* Shrinkable, unlike the label: whatever a hint adds, it is never the thing
+                    worth reading if only one of the two can fit. */}
+                {o.hint && (
+                  <span className="max-w-[50%] min-w-0 truncate text-xs text-ink-400">{o.hint}</span>
+                )}
                 <Check className="size-3.5 shrink-0 text-crimson-600 opacity-0 group-data-selected:opacity-100" aria-hidden />
               </>
             )}
diff --git a/SW.Bitween.Web/ClientApp/src/pages/exchanges/ExchangesPage.tsx b/SW.Bitween.Web/ClientApp/src/pages/exchanges/ExchangesPage.tsx
index 7d6f76fe..c4bd7390 100644
--- a/SW.Bitween.Web/ClientApp/src/pages/exchanges/ExchangesPage.tsx
+++ b/SW.Bitween.Web/ClientApp/src/pages/exchanges/ExchangesPage.tsx
@@ -69,20 +69,36 @@ export function ExchangesPage() {
    * Every promoted key any information type declares, with the types that declare it.
    * Read off the list already fetched for the information-type filter, so offering the
    * keys costs nothing — and picking from real names beats remembering how one was spelled.
+   *
+   * Narrowed to the picked information type when there is one: a short list of its own keys
+   * beats the whole catalogue with a disambiguating line on every row.
    */
   const propertyKeyOptions = useMemo(() => {
-    const owners = new Map<string, string[]>();
-    for (const t of infoTypes)
+    const scoped = query.informationTypeId
+      ? infoTypes.filter((t) => t.id === query.informationTypeId)
+      : infoTypes;
+    const owners = new Map<string, { type: string; path: string }[]>();
+    for (const t of scoped)
       for (const p of t.promotedProperties ?? []) {
         const carriers = owners.get(p.key) ?? [];
-        const name = t.code ?? t.name;
-        if (!carriers.includes(name)) carriers.push(name);
+        const type = t.code ?? t.name;
+        if (!carriers.some((c) => c.type === type)) carriers.push({ type, path: p.path });
         owners.set(p.key, carriers);
       }
     return [...owners.entries()]
       .sort(([a], [b]) => a.localeCompare(b))
-      .map(([key, carriers]) => ({ value: key, label: key, hint: carriers.join(", ") }));
-  }, [infoTypes]);
+      .map(([key, carriers]) => ({
+        value: key,
+        label: key,
+        // A second line rather than text beside the name: these run long enough
+        // ("InventoryTransactionPosted") that sharing one line left the name with no room at
+        // all. Dropped once a type is picked above — naming it again on every row says nothing.
+        sublabel: query.informationTypeId ? undefined : carriers.map((c) => c.type).join(", "),
+        // What the key actually reads out of the payload. The thing you want when a filter
+        // comes back empty and you can't tell whether the key or the value is wrong.
+        title: carriers.map((c) => `${c.type}: ${c.path}`).join("\n"),
+      }));
+  }, [infoTypes, query.informationTypeId]);
 
   /** Set (or drop) one URL param; changing any filter resets paging. */
   const setParam = (key: string, value: string | null, resetOffset = true) => {