In Aldiko the display turns black when trying to open any book in the library. "Menu" button does not produce visible effects in this state. "Back" button returns me to the library screen after two pressings. All other functions of Aldiko and of the system seem to be working fine. Including page navigation using touchscreen when the display is black! I have found this trying to switch Novel off when the display is black: the current page becomes visible behind the "Power Off" dialog window. However, when I choose "Cancel" in this dialog, the display turns black again.Aldiko worked a couple of days ago.Any ideas?