I have this strange problem with my n900. when i do not use the device, the screen use to turn off automatically. but now it stays lit.

i have disabled the auto lock feature so the phone does not lock automatically.

I use the flipclock in the night with charger plugged in. I have set the screen to stay on when charging. does that has this effect.

is there any setting or flag I can change to make it the same way.

can anyone help?