My lessons: I want to delete some

If I selected a lesson in “my lessons”, is there a possibility to delete it?
I cannot find a button for “delete”.

SORRY - I could find it now in the area for “Open”

http://image-upload.de/image/IzPYvi/93345c5a56.png

Auf den Pfeil neben “Öffnen” klicken, dann auf die Option “Lektion löschen” klicken.