Undo history panel fails if it already exists before opening file

[Formerly Kevin Yin, now disabled]

Inkscape 0.48.4 on Windows 7

1. Open Inkscape, the application.
2. Open the Undo History panel (Ctrl Shift H).
3. File->Open a file.
4. Do something in the file. Nothing will appear in the undo history panel.
5. Even if you close the undo history panel and open it, it still won't work.

[su_v (suv-lp)]

AFAICT duplicate of
- Bug #1071082 “Undo History doesn't work if open before file is opened.”
  <https://bugs.launchpad.net/inkscape/+bug/1071082>