Changes in chapter numbering cannot be undone.
Steps to reproduce:
1. Open https://bugs.documentfoundation.org/attachment.cgi?id=164277 (from bug 135725).
2. Open Tools > Chapter Numbering with tab Numbering.
3. Change the chapter numbering of Heading 1 from "Start at: 1" to "Start at: 2" (or change the number style from 1 to A or change the numbering alignment from Left to Right).
4. Click OK.
5. Try to click at the Undo button or Ctrl+Z.
Undo is not possible.
Changes in the chapter numbering should always be able to be undone by the user.
I confirm it with
Version: 220.127.116.11 (x64)
Build ID: 8061b3e9204bef6b321a21033174034a5e2ea88e
CPU threads: 4; OS: Windows 10.0 Build 19041; UI render: Skia/Raster; VCL: win
Locale: de-DE (de_DE); UI: en-GB