SUMMARY STEPS TO REPRODUCE 1. Open KAlarm. 2. Create a new Alarm or edit an existing one. 3. Manipulate (click or type into) a spinbox widget. OBSERVED RESULT Window freezes, 100% CPU usage from KAlarm on 1 thread. Spinbox doesn't respond, window doesn't render or only the frame. EXPECTED RESULT Spinbox works. SOFTWARE/OS VERSIONS KDE Plasma Version: I use LXDE but Plasma is installed, see below. KDE Frameworks Version: 5.115.0 Qt Version: 5.15.13 (compiled with: 5.15.13) kde-baseapps/noble,now 4:23.08.5+5.146ubuntu3 amd64 kde-full/noble 5:146ubuntu3 amd64 kde-plasma-desktop/noble,now 5:146ubuntu3 amd64 [installed] kde-runtime-data/now 4:17.08.3-0ubuntu1 all [residual-config] kde-runtime/now 4:17.08.3-0ubuntu1 amd64 [residual-config] Linux: lsb_release -a Distributor ID: Ubuntu Description: Ubuntu 24.04.2 LTS Codename: noble ADDITIONAL INFORMATION I tried running LANG=en_US.UTF-8 kalarm and env QT_IM_MODULE=none kalarm same thing happened.
The console output is: QPainter::begin: Paint device returned engine == 0, type: 2 QWidget::render: Cannot render with an inactive painter QPainter::begin: Paint device returned engine == 0, type: 2 QWidget::render: Cannot render with an inactive painter QPainter::begin: Paint device returned engine == 0, type: 2 QWidget::render: Cannot render with an inactive painter QPainter::begin: Paint device returned engine == 0, type: 2 QWidget::render: Cannot render with an inactive painter But it is printed well before the freeze (when opening the main window).
env QT_QPA_PLATFORMTHEME='' kalarm Makes it work. The Oxygen theme seems to be at fault.
Qt 5 is no longer supported for KAlarm. All releases are (since a year ago) based on Qt 6. Testing on an up to date Qt 6 based KDE Neon system (which is based on Ubuntu Jammy but with very recent Qt 6 development versions of all KDE software), I don't see the bug using Oxygen theme on X11. For reference, could you please supply some more information: Which are you using: X11 or Wayland? Which types of spinbox produce the bug? There are 3 types in the New Alarm dialog: 1) date 2) time (with adjustment arrows on both sides of the spinbox) 3) simple number (with adjustment arrows only on the right side of the spinbox). For example select Reminder, and then select either minutes, days or weeks (i.e. not hours/minutes). These spinboxes are also used in the Recurrence tab.
> Which are you using: X11 or Wayland? X11. > Which types of spinbox produce the bug? There are 3 types in the New Alarm dialog: > 2) time (with adjustment arrows on both sides of the spinbox) "Time" surely does it. I am not sure about the others.
So Ubuntu is on the wrong track by packaging my version of KAlarm for Qt5, right?
It seems that Ubuntu has not yet packaged any Qt6 based KDE software - even 'plucky' is still based on Qt5 and KDE Gear 23.08, which is over a year old. Debian testing now provides Qt6 stuff, so I'm sure Ubuntu will start releasing it sometime fairly soon.