System.Configuration.ApplicationSettingsBase class (http://msdn.microsoft.com/en-us/library/system.configuration.applicationsettingsbase(v=VS.110).aspx) that is used for properties doesn't work. It doesn't load properties on start or even when it is forced with Reload() method (http://msdn.microsoft.com/en-us/library/system.configuration.applicationsettingsbase.reload(v=VS.85).aspx).
It works perfectly for .net framework though.
It's a really nice class that allows to create dynamic configuration, and provides a lot of automation.
I use this class with custom settings provider (System.Configuration.SettingsProviderAttribute).
It seems that it's not a bug, unfortunately this feature is not implemented in Mono framework :(