Mint 14 + Cinnamon - screen dimming and panels disabled

[Babbles]

I'm having an annoying problem with my Mint 14 + Cinnamon environment which I can't get to the bottom of.

Randomly, when I alt-tab between windows, the screen dims by about 50% and I can no longer click on icons in the panels.

Alt-tabbing again will only brighten the screen whilst alt-tab switching is active, and then the screen dims again. Also, right clicking to bring up a context menu shows the menu in full brightness.

I can restore my desktop to working by logging out and back in again. I've tried fiddling with brightness settings but that only changes the brightness down from the current point.

I have no idea what I'm activating accidently by alt-tabbing or how to swtich it off/revert it back - any ideas?

All suggestions gratefully received!

Edit: I should probably add, I'm using Mint 14 + Cinnamon on a laptop, no external monitor - the laptop is a Lenovo T510, Intel i7 M620 @ 2.67GHz, 8GB RAM.

I've also just noticed that the dimming can happen multiple times, so the screen progressively (and randomly) gets darker and darker.

[Pixman]

Damn, I'm lucky to find your post! I have the exact same problem. It's dark all the time, but as soon as I press Alt + TAB it brightens up to normal brightness.


Previously, I updated it apt-get dist-upgrade).

Maybe a Compiz-Problem? Most probably, I guess.

ANy help appreciated.

[Essexraptor]

tried checking the power saving options ? Unplugged from the mains laptops normally have a robust power saving profile including screen brightness

menu > system tools > system settings > power

or

menu > system tools > system settings > brightness & lock

[anisrehan]

I am having the same problem.
Randomly on alt+tab, the brightness is reduced by almost 50%, and it will keep on reducing, up to the extend that screen is barely visible.
The Alb+Tab seems to activate a type of layer over the main display as nothing is selectable by mouse in sys-tray and taskbar.
I am facing this problem only after installing Linux Mint 14, 64 bit on a Intel Core 2 Duo machine.

Please help.