Bug 470833

SUMMARY
The desktop environment is Plasma X11 and using QT_IM_MODULE=ibus environment variable.

STEPS TO REPRODUCE
1. Run kwrite with QT_IM_MODULE=ibus
2. Enable ibus-anthy and Hiragana mode
3. Type "watashinamaehapendesu." keys and space key

OBSERVED RESULT
The whole the string is drawn with a black underline but the activated segment color is *not* drawn.

EXPECTED RESULT
The whole the string is drawn with a black underline and the activated segment color is drawn.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma:  Fedora 38
(available in About System)
KDE Plasma Version: plasma-workspace-5.27.5-1.fc38.x86_64
KDE Frameworks Version: 
Qt Version: qt5-qtbase-5.15.9-3.fc38.x86_64

ADDITIONAL INFORMATION

qtbase/rc/plugins/platforminputcontexts/ibus/qibusplatforminputcontext.cpp:QIBusPlatformInputContext::updatePreeditText() sends the pre-edit segment color against whole the pre-edit string using QinputMethodEvent but the color is not drawn in kwrite and konsole.

I know Wayland input-method protocol does not support the preedit colors yet but the colors had worked in Plasma X11. Maybe after Plasma Wayland was integrated, the regression was also integrated in Plasma X11.