Hello, It is not possible to insert zero width non joining space into almost all applications native to KDE such as kate. It seems an underlying bug affecting any other subsystem and application running above it. More information: https://bugreports.qt.io/browse/QTBUG-42074 P.S. It seemed the correct KDE application to file the error.
"Kate" aren't all applications. Please be more specific where it works: - Qt line edits, e.g. folder creating dialog in Dolphin - Qt text edits, e.g. inline rename box in Dolphin - Konsole terminal view - Kate/KWrite If it does not work in either of the first two cases, it is a Qt bug.
I tried the following with the results in [ ]s: - [malfunction] Qt line edits, e.g. folder creating dialog in Dolphin - [malfunction] Qt text edits, e.g. inline rename box in Dolphin - [malfunction] Konsole terminal view - [malfunction] Kate/ [did not try] KWrite I recently installed Calligra Sheets and it was working but the application itself was buggy and had to remove. If you are aware that it shouldn't be reported here then mark it resolved etc.
Thanks for the update. If the Qt bug is resolved, but Konsole/Kate/KWrite/Calligra are still not working as expected, you would need to report this separately for these applications. It is possible that fixes beyond Qt are needed.