Why did the edit cursor disappear? (Ardour2.3 on Ubuntu)

Hi everybody
I recently switched to the new Ubuntustudio 8.4 and tried Ardour 2.3. When I open or create a project, here is no visible sign of the edit cursor in the whole screen, and if i press “e” (which, i believe, means “take the edit cursor where the mouse pointer is”) it creates a new marker, but again no edit cursor. What happened?!?