Enpass V. 5.6.9 worked flawlessly. 6.1.1.451 from repository just showed up once, opened correctly and never opened again. Systemtray-Icon is visible but does not restore the window. Starting from terminal resulted in termination of process without error message. A process called enpass showed up. Killing it and restarting doesn't change anything. I checked libcurl3 is installed.
Thank god 5.6.9. still works.