fix(ui): let another tab's column save replace a toggle this tab could not save

A column toggle that localStorage refused was kept in memory and read ahead of storage, so a later save from another tab stayed hidden until this tab saved again. A storage event now drops the in-memory copy for its key, or all of them when another tab clears storage

ui/litellm-dashboard/src/components/shared/DataTable/usePersistedColumnVisibility.test.tsx

@@ -109,8 +109,9 @@ describe("usePersistedColumnVisibility", () => {
   });
 
   it("applies new defaults passed after mount", () => {
+    const initialProps: { defaults: VisibilityState } = { defaults: { spend: false } };
     const { result, rerender } = renderHook(({ defaults }) => usePersistedColumnVisibility("keys", defaults), {
-      initialProps: { defaults: { spend: false } },
+      initialProps,
     });
 
     rerender({ defaults: { name: false } });
@@ -146,6 +147,35 @@ describe("usePersistedColumnVisibility", () => {
     expect(stored("full")).toEqual({ name: false });
   });
 
+  it("shows another tab's save over a toggle this tab could not save", () => {
+    vi.spyOn(console, "warn").mockImplementation(() => {});
+    vi.spyOn(Storage.prototype, "setItem").mockImplementationOnce(() => {
+      throw new Error("QuotaExceededError");
+    });
+    const { result } = renderHook(() => usePersistedColumnVisibility("shadowed"));
+    act(() => result.current.onColumnVisibilityChange({ email: false }));
+
+    act(() => {
+      localStorage.setItem(keyFor("shadowed"), JSON.stringify({ name: false }));
+      window.dispatchEvent(new StorageEvent("storage", { key: keyFor("shadowed") }));
+    });
+
+    expect(result.current.columnVisibility).toEqual({ name: false });
+  });
+
+  it("drops a toggle this tab could not save once another tab clears storage", () => {
+    vi.spyOn(console, "warn").mockImplementation(() => {});
+    vi.spyOn(Storage.prototype, "setItem").mockImplementationOnce(() => {
+      throw new Error("QuotaExceededError");
+    });
+    const { result } = renderHook(() => usePersistedColumnVisibility("cleared", { spend: false }));
+    act(() => result.current.onColumnVisibilityChange({ email: false }));
+
+    act(() => window.dispatchEvent(new StorageEvent("storage", { key: null })));
+
+    expect(result.current.columnVisibility).toEqual({ spend: false });
+  });
+
   it("returns the defaults without throwing when storage is unavailable", () => {
     vi.spyOn(console, "warn").mockImplementation(() => {});
     vi.spyOn(Storage.prototype, "getItem").mockImplementation(() => {

ui/litellm-dashboard/src/components/shared/DataTable/usePersistedColumnVisibility.ts

@@ -18,11 +18,23 @@ function storageKey(tableId: string): string {
   return `${STORAGE_KEY_PREFIX}${tableId}`;
 }
 
+function forgetUnsavedWrite(event: StorageEvent): void {
+  if (event.key === null) {
+    unsavedWrites.clear();
+    return;
+  }
+  unsavedWrites.delete(event.key);
+}
+
 function subscribe(onChange: () => void): () => void {
-  window.addEventListener("storage", onChange);
+  const onStorage = (event: StorageEvent): void => {
+    forgetUnsavedWrite(event);
+    onChange();
+  };
+  window.addEventListener("storage", onStorage);
   window.addEventListener(LOCAL_STORAGE_EVENT, onChange);
   return () => {
-    window.removeEventListener("storage", onChange);
+    window.removeEventListener("storage", onStorage);
     window.removeEventListener(LOCAL_STORAGE_EVENT, onChange);
   };
 }