I was going through some settings of my Kubuntu 15.04 installation when I hit 'Defaults' in System Settings > Fonts. I believe this is what caused some texts to display in serif fonts, the best examples are the tab titles in Google Chrome and the texts in dialogs such as for opening files. While this did not break anything, it does look ugly.
EDIT: I've noticed that also browser drop-down menus have disappeared, I suspect it is due to the same incorrect setting.
My Fonts in System Settins read Oxygen-Sans for all but fixed width fonts, which is set to Oxygen Mono. These are sans serif fonts. Also my kdeglobals file reads:
... [General] BrowserApplication=google-chrome.desktop ColorScheme=Breeze Name=Breeze font=Oxygen-Sans,10,-1,5,50,0,0,0,0,0 menuFont=Oxygen-Sans,10,-1,5,50,0,0,0,0,0 shadeSortColumn=true smallestReadableFont=Oxygen-Sans,8,-1,5,50,0,0,0,0,0 toolBarFont=Oxygen-Sans,9,-1,5,50,0,0,0,0,0 widgetStyle=breeze ...
Does anyone know where I can change this font used in the examples above back to its default? Could this be caused by something different than the settings I've been looking at?
I'm not sure if this is important, but I did add the Kubuntu backports ppa.