Duplicated input and unable to delete the first letter on GTK4 applications

[pineapplehunter]

Description

I am having issues when using mozc on gtk4 applications. The issues are,

1. When I type in something in Japanese and press enter, it creates a duplicate input after the input and cannot be deleted until I click somewhere else with the mouse.
2. When I type in something in Japanese, pressing backspace leaves one character and cannot be deleted until I click somewhere else with the mouse.

I am trying to figure out what is causing this behavior, but I don't have much knowledge of this program. If there are any pointers or ways to debug the process, I am very happy to help.

Steps to reproduce

1. Open a gtk4 application
2. type something in Japanese
3. hit enter, or try to delete

Expected behavior

• When enter is hit, it should not be duplicated
• When deleting, it should delete everything

Actual behavior

See Screenshots.

Screenshots

The enter case The delete case

Version or commit-id

Tested both on mozc built on tag 2.29.5374.102 and latest git.

Environment

• OS: NixOS unstable
• IMF (for Linux) : IBus
• Related Applications: All GTK4 Applications. GTK3 applications and other applications with different frameworks are not affected.

Investigations

• Whether this issue happens on both Ibus and other IMF (e.g. Fcitx, uim).
  • no, there were no issues on fcitx5 (different mozc version)
• Whether this issue happens on other IMEs (e.g. Anthy, SKK).
  • no, ibus with anthy seem to be working correctly
• What applications this issue happens on (e.g. Chromium, gedit).
  • GTK4 or libadwaita applications?
• What applications this issue does not happen on (e.g. Chromium, gedit).
  • Firefox, chrome, gtk3 applications, qt applications
• (optional) What versions or commit-ids this issue did not happen on (e.g. Mozc-2.28.4960.100+24.11.oss).
  • I don't know.

Additional context

Add any other context about the problem here.