cullmann added a comment.
I checked a bit what Qt does: bool QInputControl::isAcceptableInput(const QKeyEvent *event) const { const QString text = event->text(); if (text.isEmpty()) return false; const QChar c = text.at(0); // Formatting characters such as ZWNJ, ZWJ, RLM, etc. This needs to go before the // next test, since CTRL+SHIFT is sometimes used to input it on Windows. if (c.category() == QChar::Other_Format) return true; // QTBUG-35734: ignore Ctrl/Ctrl+Shift; accept only AltGr (Alt+Ctrl) on German keyboards if (event->modifiers() == Qt::ControlModifier || event->modifiers() == (Qt::ShiftModifier | Qt::ControlModifier)) { return false; } if (c.isPrint()) return true; if (c.category() == QChar::Other_PrivateUse) return true; if (m_type == TextEdit && c == QLatin1Char('\t')) return true; return false; } is applied on key events. REPOSITORY R39 KTextEditor REVISION DETAIL https://phabricator.kde.org/D23472 To: ahmadsamir, #ktexteditor, dhaumann, cullmann Cc: kde-frameworks-devel, kwrite-devel, LeGast00n, GB_2, domson, michaelh, ngraham, bruns, demsking, cullmann, sars, dhaumann