When running DOSBox it will exit fullscreen after about 10 minutes. The only way to get DOSBox back to fullscreen is to minimise it, and restore it. Once DOSBox is restored the same problem occurs again.

Using DOSBox 0.73 on Ubuntu 10.04. I suspect the issue may be related to SDL as a similar issue occurs when running Neverwinter Nights.

I think that SDL 1.2 is being used but I am not entirely sure.