The bug: https://github.com/LibVNC/libvncserver/issues/45 The fix: https://github.com/maxnet/libvncserver/commit/4674d4632b9ffc6779d9c9f79b8ebb53c12e29b2
I applied that patch to the libvnc package in ubuntu utopic and it fixed the problem for me. My bug report in KDE/KRDC: https://bugs.kde.org/show_bug.cgi?id=343376 Thanks!
