Recently on openSUSE Firefox updated to 51.0.1 and it now uses GTK3 style :( , I have no idea how to configure KDE4 in general, and looking it badly. :'(
Before that geany and chromium migrated to it, and more and more applications migrate from gtk2 to gtk3. :(
GTK-3.22.x already stabilized ABI and API, and will not be changed and is just right for it to make a theme that would gtk3-applications looking is nice.
And in KDE5 also need full support QtCurve.
Recently on openSUSE Firefox updated to 51.0.1 and it now uses GTK3 style :( , I have no idea how to configure KDE4 in general, and looking it badly. :'(
Before that geany and chromium migrated to it, and more and more applications migrate from gtk2 to gtk3. :(
GTK-3.22.x already stabilized ABI and API, and will not be changed and is just right for it to make a theme that would gtk3-applications looking is nice.
And in KDE5 also need full support QtCurve.