"Styles" panel disappeared

[GuidoGonzato]

Description of the bug

Releases equal to or newer than 702c4c5 make the Style panel disappear, and there's apparently no way to get the Styles back.
I "solved" by rolling back to release Ansel f7669af, which is the last release unaffected from another bug I'll report (Ctrl + mouse and Shift + mouse not working). I also had to remove $HOME/.config/ansel. Very bad bug. Good thing I had a backup of my styles.

To Reproduce

Start Ansel 702c4c5 or newer; the Style panel is gone.

Expected behavior

The Style panel should not vanish.

Context

Screenshots

Screencast

Which commit introduced the error

Apparently, Ansel 702c4c5

System

• darktable version : 702c4c5
• OS : Linux 5.15.0-89-generic
• Linux - Distro : Linux Mint 21.2 (VIctoria)
• Memory : 8GB
• Graphics card : NVIDIA GeForce 920M
• Graphics driver : nvidia-driver-470
• OpenCL installed : unknown
• OpenCL activated : unknown
• Xorg : 1:7.7+23ubuntu2
• Desktop : Mate
• GTK+ : unknown
• gcc : unknown
• cflags : unknown
• CMAKE_BUILD_TYPE : unknown
  
  

Additional context

• Can you reproduce with another darktable version(s)? yes with version x-y-z / no
• Can you reproduce with a RAW or Jpeg or both? RAW-file-format/Jpeg/both
• Are the steps above reproducible with a fresh edit (i.e. after discarding history)? yes/no
• If the issue is with the output image, attach an XMP file if (you'll have to change the extension to .txt)
• Is the issue still present using an empty/new config-dir (e.g. start darktable with --configdir "/tmp")? yes/no
• Do you use lua scripts?
  • What lua scripts start automatically?
  • What lua scripts were running when the bug occurred?

[aurelienpierre]

Styles are temporarily unavailble until the history read-write is made thread-safe. They will re-appear in global menu.

[GuidoGonzato]

Fine, thanks.

[aurelienpierre]

Part of #262. Closing here.