When using both the enabler and telnet to manage the taskbar there are instances where the device is unable to connect to the host and there is a black screen with a solid white box in the upper left hand corner of the screen.
There is also a faint white box that moves up the center of the screen.
You can only use one or the other to manage the taskbar. The resolution could be to unlock the taskbar with the enabler and then have the enabler auto launch the telnet application with the menu hidden.
This will avoid two sources trying to manage the same code and also prevent users from being able to access the taskbar.