Today, I tried to reproduce the bug - and I failed. I uninstalled the plasma widget, and started the GNOME nm-applet, and everything worked smoothly. And - surprise, surprise - even after I reinstalled the plasma widget, everything works fine when using the GNOME nm-applet. It doesn't loose any settings, and conection works wonderfully.
So finally, it looks as though there is again a way to connect to OpenVPN with kubuntu. Great!
Today, I tried to reproduce the bug - and I failed. I uninstalled the plasma widget, and started the GNOME nm-applet, and everything worked smoothly. And - surprise, surprise - even after I reinstalled the plasma widget, everything works fine when using the GNOME nm-applet. It doesn't loose any settings, and conection works wonderfully.
So finally, it looks as though there is again a way to connect to OpenVPN with kubuntu. Great!
I think this bug can be closed.