TeamViewer does not close, just minimizing.

Hi, if I close teamviewer 14 (Kubuntu 16.04), it only minimizes to tray instead of closing. I did neither activate auto start nor any other option for unattended access. The option "Disallow terminating teamviewer" is NOT checked. I always have to right click the tray icon and close it there manually. I found no option to really close if I close the window like any other software.