When starting kstars 2.3.0 with a position currently below the horizon the dialoge "Initial position is below horizon" is frozen. There are no buttons, the background from the desktop is visible, the dialoge is not painted correctly, it must be killed by the system. Kubuntu 15.10, KDE Plasma 5.4, Kernel 4.2.0-27 generic. It definitively works under Linux Mint Cinnamon 17.3.
Please upgrade to a more recent version of KStars and see if you can replicate the problem.
Hello, in Version 2.4.0 (installed within Kubuntu 16.04) this seems to be fixed. Thank you very much, Manfred Dings