I have some really big application mixture of c# and j#.
Sometimes when I close it, there are some threads that are not closed and they are hanging in the task mana
You should close your threads gracefully, but just want you and others to know the way that is not recommended but possible:
on your OnClose Handler:
System.Diagnostics.Process.GetCurrentProcess().Kill();
I totally prefer Cody Gray way of doing it.