The default value is 10 mins, so you might have to change that in the settings dialog of xfce4-power-manager to get a different value.
You can always control whether the values in the power manager are applied correctly by running "xset q | grep timeout" in the terminal. (Note that the values by xset are seconds while the power manager converts that to minutes, for convenience).
The default value is 10 mins, so you might have to change that in the settings dialog of xfce4-power-manager to get a different value.
You can always control whether the values in the power manager are applied correctly by running "xset q | grep timeout" in the terminal. (Note that the values by xset are seconds while the power manager converts that to minutes, for convenience).