dfaure added a comment.
I've been hitting a very similar bug where a Qt app was trying to use a bold font, and this had no effect when running in a plasma workspace, because of this code in kfontsettingsdata.cpp. Testcase (couldn't be simpler...) http://www.davidfaure.fr/2018/qlabel_inherited_font.cpp with this in ~/.config/kdeglobals: [General] font=Noto Sans,7,-1,5,50,0,0,0,0,0,Regular Unfortunately, this patch doesn't fix it. The text still isn't bold. Workaround: enabling the line that calls QApplication::setDesktopSettingsAware(false). Proof that this code is guilty: commenting out the fromString line makes it work, too. What really confuses me is: why isn't it all set up so that this platform-plugin code provides *default* fonts, and so that what apps do overrides that? (sorry that I didn't dig as far as some of you guys did) REPOSITORY R135 Integration for Qt applications in Plasma REVISION DETAIL https://phabricator.kde.org/D9070 To: rjvbb, #frameworks, davidedmundson, graesslin, cfeck, dfaure Cc: abetts, anthonyfieroni, ngraham, cfeck, fvogt, plasma-devel, ZrenBot, progwolff, lesliezhai, ali-mohamed, jensreuterberg, sebas, apol, mart