URL: https://chat.deepseek.com/

Browser / Version: Firefox 151.0
Operating System: Windows 11
Tested Another Browser: Yes Chrome

Problem type: Site is not usable
Description: Unable to type
Steps to Reproduce:
Edit/redact previous prompts form - Ctrl+Z not work - undo modifying text not work. In context menu on form "Undo/Redo" is always grayed (not accessed). But main form (new prompt) - work correctly.

1. Send some prompt and wait answer.
2. Press button "Edit" on initial prompt and edit text (replace any word).
3. Press Ctrl+Z or click "Undo" in context Menu.
   Expected behavior: revert to original text (word).

View the screenshot

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