I get a stackoverflow exception on following commented line.

namespace Football_Manager_WFA
    public partial class Settings : Form
        Color def_bgdColor = SystemColors.Control;
        Color def_fontColor = Color.Black; // ERROR
        static FontFamily fontFamily = FontFamily.GenericSansSerif;
        Font def_fontType = new Font(fontFamily, 8.0f);

A StackOverflowException is usually caused by recursive function calls. Try taking a look at the method(s) that instantiate a new instance of the Settings class (or post them here). There is probably something that calls the method again, or another method that ends up calling the method.

If your IDE shows gives you a call stack, post that too. I'm pretty sure Visual Studio won't, and since .NET 2.0, you can't catch it.

Thanks. The problem was as you said nmaillet.

I initialized Settings form two times, so just deleted one of them, and it works now.