Ever since the update which suggested that I migrate from XS to VSforMac, breakpoints have not been working for me, I use Xamarin.Mac Full framework. I also had to add some CscTool property (https://forums.xamarin.com/discussion/95231/compile-error-after-updating-to-15-2).
The breakpoints turn hollow when I start debugging.
System.Diagnostics.Debugger.Break(); works, but I can't see the values of variables, so it's more or less useless.
Breakspoints do work if I create a new project.
I'm currently using the alpha channel.