diff --git a/client/src/Providers/UploadModalContext.tsx b/client/src/Providers/UploadModalContext.tsx
index d202f26405..70479b2f0d 100644
--- a/client/src/Providers/UploadModalContext.tsx
+++ b/client/src/Providers/UploadModalContext.tsx
@@ -1,4 +1,12 @@
-import React, { createContext, useCallback, useContext, useMemo, useState } from 'react';
+import React, {
+  useRef,
+  useMemo,
+  useState,
+  useEffect,
+  useContext,
+  useCallback,
+  createContext,
+} from 'react';
 
 interface UploadModalContextValue {
   isVisible: boolean;
@@ -19,8 +27,20 @@ const UploadModalContext = createContext<UploadModalContextValue>(defaultValue);
 export function UploadModalProvider({ children }: { children: React.ReactNode }) {
   const [isVisible, setIsVisible] = useState(false);
   const [files, setFiles] = useState<File[]>([]);
+  /**
+   * A paste or a drop opens this dialog programmatically, so there is no
+   * `Dialog.Trigger` for Radix to hand focus back to — and its modal content
+   * always cancels the default restore in favour of that missing trigger,
+   * dropping focus on `document.body`. The composer's Enter-to-send is a
+   * textarea key handler, so the user is left holding a full draft and an
+   * enabled send button that Enter no longer reaches, until they click back
+   * into the composer. Remember where the upload was started from instead.
+   */
+  const returnFocusRef = useRef<HTMLElement | null>(null);
 
   const openModal = useCallback((nextFiles: File[]) => {
+    const active = document.activeElement;
+    returnFocusRef.current = active instanceof HTMLElement ? active : null;
     setFiles(nextFiles);
     setIsVisible(true);
   }, []);
@@ -30,6 +50,22 @@ export function UploadModalProvider({ children }: { children: React.ReactNode })
     setFiles([]);
   }, []);
 
+  useEffect(() => {
+    if (isVisible) {
+      return;
+    }
+    const element = returnFocusRef.current;
+    returnFocusRef.current = null;
+    if (element == null || !element.isConnected) {
+      return;
+    }
+    /** Radix restores focus from the dialog's own unmount cleanup, deferred by
+     * a timeout of its own. This effect runs after that cleanup, so the queued
+     * restore lands last. */
+    const timeout = setTimeout(() => element.focus({ preventScroll: true }), 0);
+    return () => clearTimeout(timeout);
+  }, [isVisible]);
+
   const value = useMemo<UploadModalContextValue>(
     () => ({ isVisible, files, openModal, closeModal }),
     [isVisible, files, openModal, closeModal],
diff --git a/client/src/components/Chat/Input/__tests__/ChatForm.pasteUpload.spec.tsx b/client/src/components/Chat/Input/__tests__/ChatForm.pasteUpload.spec.tsx
new file mode 100644
index 0000000000..dbb077b925
--- /dev/null
+++ b/client/src/components/Chat/Input/__tests__/ChatForm.pasteUpload.spec.tsx
@@ -0,0 +1,212 @@
+import React, { useMemo, useState } from 'react';
+import '@testing-library/jest-dom';
+import { DndProvider } from 'react-dnd';
+import { useForm } from 'react-hook-form';
+import { RecoilRoot, useRecoilState } from 'recoil';
+import userEvent from '@testing-library/user-event';
+import { HTML5Backend } from 'react-dnd-html5-backend';
+import { BrowserRouter as Router } from 'react-router-dom';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { render, screen, waitFor, fireEvent } from '@testing-library/react';
+import { QueryKeys, FileSources, EModelEndpoint } from 'librechat-data-provider';
+import type { TFile, TFileUpload, TConversation } from 'librechat-data-provider';
+import type { ChatFormValues } from '~/common';
+import { ChatContext, ChatFormProvider } from '~/Providers';
+import { AuthContextProvider } from '~/hooks/AuthContext';
+import DragDropWrapper from '../Files/DragDropWrapper';
+import ChatForm from '../ChatForm';
+import store from '~/store';
+
+const mockUpload = jest.fn();
+const mockAsk = jest.fn();
+
+jest.mock('librechat-data-provider', () => {
+  const actual = jest.requireActual('librechat-data-provider');
+  return {
+    ...actual,
+    dataService: {
+      ...actual.dataService,
+      uploadImage: (...args: unknown[]) => mockUpload(...args),
+      uploadFile: (...args: unknown[]) => mockUpload(...args),
+    },
+  };
+});
+
+const conversation = {
+  conversationId: 'new',
+  endpoint: EModelEndpoint.openAI,
+  model: 'gpt-4o',
+  title: 'New Chat',
+} as TConversation;
+
+const uploadResponse = {
+  message: 'File uploaded',
+  file_id: 'server-file-id',
+  temp_file_id: 'temp-file-id',
+  filename: 'pasted.png',
+  filepath: '/images/pasted.png',
+  type: 'image/png',
+  bytes: 2048,
+  height: 100,
+  width: 100,
+  source: FileSources.local,
+  embedded: false,
+} as unknown as TFileUpload;
+
+/** jsdom never decodes images; the app only starts the upload once one loads. */
+class StubImage {
+  onload: (() => void) | null = null;
+  onerror: (() => void) | null = null;
+  width = 100;
+  height = 100;
+  set src(_value: string) {
+    setTimeout(() => this.onload?.(), 0);
+  }
+}
+
+function Harness() {
+  const [files, setFiles] = useRecoilState(store.filesByIndex(0));
+  const [isSubmitting] = useRecoilState(store.isSubmittingFamily(0));
+  const [, setFilesLoading] = useState(false);
+  const methods = useForm<ChatFormValues>({ defaultValues: { text: '' } });
+
+  const chatHelpers = useMemo(
+    () =>
+      ({
+        index: 0,
+        conversation,
+        setConversation: () => undefined,
+        files,
+        setFiles,
+        isSubmitting,
+        setIsSubmitting: () => undefined,
+        filesLoading: false,
+        setFilesLoading,
+        newConversation: () => undefined,
+        handleStopGenerating: () => undefined,
+        stopGenerating: () => undefined,
+        getMessages: () => [],
+        setMessages: () => undefined,
+        ask: mockAsk,
+        regenerate: () => undefined,
+        setSiblingIdx: () => undefined,
+        showPopover: false,
+        setShowPopover: () => undefined,
+        abortScroll: false,
+        setAbortScroll: () => undefined,
+        preset: null,
+        setPreset: () => undefined,
+        optionSettings: {},
+        setOptionSettings: () => undefined,
+        handleRegenerate: () => undefined,
+        handleContinue: () => undefined,
+      }) as unknown as React.ContextType<typeof ChatContext>,
+    [files, setFiles, isSubmitting],
+  );
+
+  return (
+    <ChatFormProvider {...methods}>
+      <ChatContext.Provider value={chatHelpers}>
+        <DragDropWrapper>
+          <ChatForm index={0} />
+        </DragDropWrapper>
+      </ChatContext.Provider>
+    </ChatFormProvider>
+  );
+}
+
+function renderComposer() {
+  const queryClient = new QueryClient({
+    defaultOptions: { queries: { retry: false }, mutations: { retry: false } },
+  });
+  queryClient.setQueryData([QueryKeys.fileConfig], {});
+  queryClient.setQueryData<TFile[]>([QueryKeys.files], []);
+  queryClient.setQueryData([QueryKeys.endpoints], { [EModelEndpoint.openAI]: { order: 0 } });
+
+  return render(
+    <QueryClientProvider client={queryClient}>
+      <RecoilRoot>
+        <Router>
+          <AuthContextProvider authConfig={{ loginRedirect: '', test: true }}>
+            <DndProvider backend={HTML5Backend}>
+              <Harness />
+            </DndProvider>
+          </AuthContextProvider>
+        </Router>
+      </RecoilRoot>
+    </QueryClientProvider>,
+  );
+}
+
+const pasteImage = (textarea: HTMLElement) => {
+  const file = new File(['image-bytes'], 'pasted.png', { type: 'image/png' });
+  const event = new Event('paste', { bubbles: true, cancelable: true });
+  Object.defineProperty(event, 'clipboardData', {
+    value: {
+      files: [file],
+      items: [{ kind: 'file', type: 'image/png', getAsFile: () => file }],
+      types: ['Files'],
+      getData: () => '',
+    },
+  });
+  fireEvent(textarea, event);
+};
+
+/**
+ * The upload-destination dialog is opened by the paste itself, so Radix has no
+ * trigger to return focus to when it closes and used to leave focus on
+ * `document.body` — which reads to the user as "the send button is enabled but
+ * Enter does nothing", since Enter-to-send is a textarea key handler.
+ */
+describe('composer focus after a pasted upload', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    global.URL.createObjectURL = jest.fn(() => 'blob:preview');
+    global.URL.revokeObjectURL = jest.fn();
+    (global as unknown as { Image: unknown }).Image = StubImage;
+    mockUpload.mockReset();
+    mockAsk.mockReset();
+    mockUpload.mockImplementation((body: FormData) =>
+      Promise.resolve({ ...uploadResponse, temp_file_id: body.get('file_id') as string }),
+    );
+  });
+
+  test('returns focus to the composer when the upload dialog closes', async () => {
+    renderComposer();
+
+    const textarea = await screen.findByTestId('text-input');
+    await userEvent.click(textarea);
+    await userEvent.type(textarea, 'hi');
+    expect(textarea).toHaveFocus();
+
+    pasteImage(textarea);
+    const [option] = await screen.findAllByRole('button', { name: /upload/i });
+    expect(textarea).not.toHaveFocus();
+
+    await userEvent.click(option);
+    await waitFor(() => expect(mockUpload).toHaveBeenCalled());
+    await waitFor(() => expect(textarea).toHaveFocus());
+  }, 20000);
+
+  test('Enter still sends after a pasted upload, with no further typing', async () => {
+    renderComposer();
+
+    const textarea = await screen.findByTestId('text-input');
+    await userEvent.click(textarea);
+    await userEvent.type(textarea, 'hi');
+
+    pasteImage(textarea);
+    const [option] = await screen.findAllByRole('button', { name: /upload/i });
+    await userEvent.click(option);
+    await waitFor(() => expect(mockUpload).toHaveBeenCalled());
+    await waitFor(() => expect(screen.getByTestId('send-button')).toBeEnabled());
+    await waitFor(() => expect(textarea).toHaveFocus());
+
+    /** Straight to the keyboard: clicking or typing first would restore focus
+     * on its own and hide the regression this covers. */
+    fireEvent.keyDown(document.activeElement as Element, { key: 'Enter', code: 'Enter' });
+
+    await waitFor(() => expect(mockAsk).toHaveBeenCalled());
+    expect(mockAsk.mock.calls[0][0]).toEqual(expect.objectContaining({ text: 'hi' }));
+  }, 20000);
+});