Debugging GTK UI rendering in KDE4

There're several things in KDE4, that can affect UI rendering. Each of them should be checked whether it triggers the bug. Any additional information could help to narrow the issue.

Desktop Effects

KDE4 supports different window composition backends. They're controlled in SystemSettings / Desktop / Desktop Effects:

Try Enable/Disable it and check whether this triggers bug. In "Anvanced" options, when effects are enabled try different compositing backends (XRender, OpenGL...) No need to restart, just change the setting and hit "Apply" button.

Video Driver

If possible, try using different video driver and check whether this affects the bug. I.e. try nouveau instead nvidia, or try booting vesa.

GTK rendering

KDE4 allows to configure look of GTK applications: SystemSettings / Appearance / GTK+ Appearance:

If it's not there install the correct kde config module:

• Debian: apt-get install kde-config-gtk-style
• Ubuntu: aptitude install kde-config-gtk
• Fedora: yum install kcm-gtk

Try different widget styles (oxygen-gtk, qt-curve...) and check whether bug disappears when you change widget style.

Note: those settings are saved in file ~/.gtkrc-2.0-kde* so if you want to undo the changes just delete that file.

GTK environment

Trying to make GTK apps look same as KDE apps KDE4 changes GTK styles using environment variables GTK_RC_FILES and GTK2_RC_FILES. Check whether anything changes when you unset it. To check that run your testprogram like this: env GTK_RC_FILES="" GTK2_RC_FILES="" testprogram

No KDE

If nothing else affects the bug try booting without KDE. For example install some small desktop environment (e.g. icewm) or select in X Safe Mode session on login screen and check whether the bug is still there.

LiveCD

If all previous attemts failed it could be that some part of your system or settings is to blame. To check that try booting from a LiveCD and check whether the bug can be reproduced there.

This article originally written by fedorauser