[PROBLEM] Display configuration

[Lanzelet]

Hey guys,

I am running Xbian on my Raspberry Pi Model B. All worked fine but in the last weeks I discovered a really nasty problem.

Everytime I start my Raspi, the dahsboard doesn't fit anymore to my TV. So I go to the System-Setting and configure the edges to fit my TV-Screen. After this I browse through the dashboard and suddently the Screen is getting bigger again and I have to redo the configuration.
First of all, xbian seems to stopped saving my adjustments and second, often, but not everytime it suddently getting bigger again.

I stopped using my Raspberry a few weeks, because I was frustrated to do the configuration at every startup, but now I want to use it again. Any Idea, how I can solve this problem?