Thanks for the info. I will have a closer look at the screen backlight. I definitely couldn't see it getting dimmer. There is also an "auto adjust backlight" setting but I don't know what that does.
The idea of saving power by turning it on and off with the top button is a good one, especially if/while there is no power saving mode in the software itself. What would be handy in that case would be an audible sound when a position report is sent, so you can tell without seeing the screen when it's OK to turn it off again.
When I said the app had closed it really had closed - I used the task switcher to try to activate it and it had just vanished. I don't know if anything might have pressed the X button. The slip-in cases are a pretty tight fit.
By the way Lynn why is it that I don't see the battery status indicator on the APRSISCE title bar (which incidentally says APRSIS for Win32 for some strange reason)? I have to switch to the Home screen for a quick check on the battery status.