I too suffer from this bug with KDE5+Breeze in Inkscape trunk. Setting the GTK style to QtCurve does the job even though it is not as well implemented a GTK theme as oxygen-gtk... But at least I can use guides in Inkscape.
I too suffer from this bug with KDE5+Breeze in Inkscape trunk. Setting the GTK style to QtCurve does the job even though it is not as well implemented a GTK theme as oxygen-gtk... But at least I can use guides in Inkscape.