Backkey and black screen

[danGA5e9c]

Can anyone explain what is going on with the backkey when it is pressed? if i do not catch it, then when the user returns to the app they have a black screen. If i intercept the message with a backkey handler then Android does not behave as expected. Am I suppose to issue a quit command in the backkey handler? Or is their another reason why I get a black screen after the user presses the BackKey and then tries to return to the app?

thanks in advance.