bug(linux): [Sundanese] Backspace issue; likely affects other layouts as well

[Ilhamkang]

I have been using the Sundanese script and Sundanese-Latin layouts via Keyman on both Linux and Windows for a long time. However, I have encountered an issue on Linux Mint 22.2 (linux kernel 6.8.0-90-generic) where the backspace key frequently skips several characters due to the iBus buffer. I found that forcing the backspace to ignore the buffer (embeded preedit text) fixes this locally on my machine.

Additionally, there is a bug when highlighting text: instead of deleting the selected character or word, the backspace key deletes the character immediately preceding the selection, leaving the highlighted text intact.

I am not sure if this bug is reproducible on other machines. Hopefully, there is a solution for this issue.

[mcdurdin]

Note that the proposed workaround, to emit U+0008 (in keymanapp/keyboards#3834), would lead to other compatibility issues, such as emitting a literal Ctrl+H in some apps/platforms, rather than backspacing.

See also: https://help.keyman.com/developer/language/guide/control-keys#toc-control-characters-in-output

cc: @LornaSIL

[ermshiperete]

@Ilhamkang In what version of Keyman do you see the backspace misbehaving? And in what app? Could you create a screen-recording that shows the problem?

I tried to reproduce in Linux Mint 22.1 (Cinnamon desktop), Kernel 6.8.0.87 in gedit with Keyman 17.0.295 but backspace seems to work.

[ermshiperete]

Regarding the problems typing backspace with a selection, there are several issues open: #8827, #10008. A workaround is to use the Delete key instead of Backspace to delete the selection.

[Ilhamkang]

@ermshiperete thank you for trying to reproduce it. I found the case in various apps, including LibreOffice, Firefox, Xed Text Editor, as well as in Nemo. However it's not occurred in Brave, Chrome and Opera.

Here is the recorded session I made in Xed:

simplescreenrecorder-2026-03.webm

here is the Keyman version on my machine:

~$ apt show ibus-keyman
Package: ibus-keyman
Version: 18.0.245-1~sil1~noble
Priority: optional
Section: text
Source: keyman
Maintainer: Debian Input Method Team <debian-input-method@lists.debian.org>
Installed-Size: 95,2 kB
Provides: keyman-engine
Depends: ibus (>= 1.3.7), libkeymancore2 (= 18.0.245-1~sil1~noble), keyman-system-service (= 18.0.245-1~sil1~noble), libc6 (>= 2.34), libglib2.0-0t64 (>= 2.79.0), libgtk-3-0t64 (>= 3.0.0), libibus-1.0-5 (>= 1.5.14), libicu74 (>= 74.1-1~), libjson-glib-1.0-0 (>= 1.5.2), libstdc++6 (>= 4.1.1), libsystemd0 (>= 221)