The ZERO WIDTH NON-JOINER character (U+200C) is very useful in arabic-like languages. However, if you assin a key to it and type it in a KDE5-base app eg kate, nothing will be entered. However there is not such problem with gedit and other non-kde apps. Reproducible: Always Steps to Reproduce: 1. Switch to Arabic keyboard layout in Kububtu 16.04 2. Press shift+space between any Arabic word in `kate`. 3. Press shift+space between any Arabic word in `gedit`. 4. Compare the results. 5. Copy what you type in gedit and paste it in `kate`. There is no problem when pasting. Just typing ZERO WIDTH NON-JOINER and similar characters is prohibited in `kate`. Actual Results: Nothing is typed when you press a key assigned for typing ZERO WIDTH NON-JOINER in kate and other KDE5-based apps. There is no such problem in `gedit` and other gnome apps. there was not such problem in KDE4 in Ubuntu 14.04.
Does it work in QLineEdit, e.g. in the search box in systemsettings5?
(In reply to Christoph Feck from comment #1) > Does it work in QLineEdit, e.g. in the search box in systemsettings5? No. However, Qt4-based apps have no such problem.
Then it is a regression in Qt5. Please report this directly to Qt developers via https://bugreports.qt.io/