I progress a little on the problem, I have now dual screen. But the solution is not satisfying.
So I have two display:
1. my laptop 15" 4:3 1400x1050 resolution
2. my external VGA monitor 22" 16:10 1600x1050 resolution
* With the external screen unplugged, I set the laptop screen resolution to 1024x768
* I plugged the external monitor to my laptop and started the Monitor Preferences. The external monitor is automatically detected with the correct resolution.
If I try to change the laptop resolution, the two monitor get corrupted as described by pixiesnoot. Even moving the external monitor from right to left is not possible.
So I have now dual monitor, but not with the correct resolution...
I progress a little on the problem, I have now dual screen. But the solution is not satisfying.
So I have two display:
1. my laptop 15" 4:3 1400x1050 resolution
2. my external VGA monitor 22" 16:10 1600x1050 resolution
* With the external screen unplugged, I set the laptop screen resolution to 1024x768
* I plugged the external monitor to my laptop and started the Monitor Preferences. The external monitor is automatically detected with the correct resolution.
If I try to change the laptop resolution, the two monitor get corrupted as described by pixiesnoot. Even moving the external monitor from right to left is not possible.
So I have now dual monitor, but not with the correct resolution...