@Len, I could not reproduce it on my own system with Xfce installed, but I can now reproduce it on Xubuntu daily CD.
According to D-Bus monitor, qjackctl doesn't even create a tray icon before everything hangs. Looking at the code, I suppose such behavior may be a result of this call in src/qjackctl.cpp: XGrabServer(m_pDisplay); m_wOwner = m_pWidget->winId(); XSetSelectionOwner(m_pDisplay, m_aUnique, m_wOwner, CurrentTime); In this code, m_pWidget is hidden so has no winId, and calling XSetSelectionOwner with m_wOwner=0 may result in blocked X11 session. (Because of bad design of X11, apps can do that… In Wayland this isn't possible). I very much recommend to not use X11 API directly in Qt applications, and use what Qt provides instead. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to qtbase-opensource-src in Ubuntu. https://bugs.launchpad.net/bugs/1546328 Title: Systray option does not work. Status in Ubuntu Studio: New Status in qjackctl package in Ubuntu: Confirmed Status in qtbase-opensource-src package in Ubuntu: Invalid Bug description: Setting Qjackctl to "Enable system tray icon" does not display Qjackctl's icon and the menu provided by qjackctl from systray is blank. Further setting Qjackctl to "Start minimized to system tray" makes the application unusable. A reboot after Qjackctl to "Enable system tray icon" and "Start minimized to system tray" are set, starting Qjackctl not only doesn't show Qjackctl's icon, but the mouse stops working correctly: The mouse moves ok, but does not have any hover effect or clicks so the menu no longer works and the only way to kill qjackctl is with control-alt-F1 (which does still work). Qjackctl is the main application used for controlling Jackd or jackdbus for those using any of the pro audio software. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: qjackctl 0.4.1-1ubuntu1 ProcVersionSignature: Ubuntu 4.4.0-4.19-lowlatency 4.4.1 Uname: Linux 4.4.0-4-lowlatency x86_64 ApportVersion: 2.20-0ubuntu3 Architecture: amd64 CurrentDesktop: XFCE Date: Tue Feb 16 14:30:46 2016 InstallationDate: Installed on 2015-11-19 (89 days ago) InstallationMedia: Ubuntu-Studio 16.04 LTS "Xenial Xerus" - Alpha amd64 (20151118) SourcePackage: qjackctl UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntustudio/+bug/1546328/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp