xfce4-power-manager-0.8.1-alt1

Now, the warning about a low battery level is shown for about 10 seconds.

It's not much enough, since it is very probable that user doesn't see it (because he doesn't look at the screen for these 10 seconds).

I suggest to make the warning message last longer: perhaps, 1 minute, or make it dialogue -- so that a user explicitly clicks on a button that closes the warning.