Cryptmator UI is not accessabe

When I start Cryptomator UI does not show up. Cryptomator starts and I can see it in the task bar. I can acess Einstellungen but not Anzeigen.
What is wrong?
This beavior I have wirh 2.9.1 and downgrade to 1.6.17 did not improve behavior.

Update: I found UI when I attache my Laptop to a big screen. Windows seemes to hide UI in not visible sreeen area. Is this a Windows buf or a Cryptomator bug?