https://bugs.kde.org/show_bug.cgi?id=420075
--- Comment #2 from Carsten Pfeiffer <pfeif...@kde.org> --- I can confirm this on Debian with - Kontact 5.19.3 (21.12.3) - KDE Frameworks 5.94.0 - Qt 5.15.4 (built against 5.15.4) Every backtrace I take when it's stuck contains QSyntaxHighlighter::rehighlight(). And indeed, shortening the email makes the problem go away. #0 0x00007f7bb7ded2f7 in QTextBlock::textDirection() const () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #1 0x00007f7bb7e25722 in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #2 0x00007f7bb7e279a5 in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #3 0x00007f7bb7e2f7a7 in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #4 0x00007f7bb7e2fd9a in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #5 0x00007f7bb7e303c0 in QTextDocumentLayout::doLayout(int, int, int) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #6 0x00007f7bb7e3170b in QTextDocumentLayout::documentChanged(int, int, int) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #7 0x00007f7bb7df242d in QTextDocument::markContentsDirty(int, int) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #8 0x00007f7bb7e526bb in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #9 0x00007f7bb7e5305f in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #10 0x00007f7bb7e531f7 in ?? () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #11 0x00007f7bb7e53599 in QSyntaxHighlighter::rehighlight() () from /lib/x86_64-linux-gnu/libQt5Gui.so.5 #12 0x00007f7ba7de6431 in Sonnet::Highlighter::slotRehighlight() () from /lib/x86_64-linux-gnu/libKF5SonnetUi.so.5 #13 0x00007f7bb78de013 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5 #14 0x00007f7bb78e1eca in QTimer::timeout(QTimer::QPrivateSignal) () from /lib/x86_64-linux-gnu/libQt5Core.so.5 -- You are receiving this mail because: You are watching all bug changes.