For those who use nested static classes to organize/seperate constants. If you need to Bind into nested static classes, It seems you need to use a plus (+) operator instead of the dot (.) operator to access the nested class:
{Binding Source={x:Static namespace:StaticClass+NestedStaticClasses.StaticVar}}
Example:
public static class StaticClass
{
public static class NestedStaticClasses
{
public static readonly int StaticVar= 0;
}
}