Collection was modified; enumeration operation may not execute.
at <Unknown>.ArrayListEnumeratorSimple.MoveNext  (IL offset: 0x0)
at <Unknown>.Application.Exit  (IL offset: 0x5e)
at <Unknown>.ThreadContext.OnThreadException  (IL offset: 0x8f)
at <Unknown>.TimerNativeWindow.OnThreadException  (IL offset: 0x6)
at <Unknown>.NativeWindow.Callback  (IL offset: 0x6b)
at <Unknown>.User32.DispatchMessageW  (IL offset: 0xffffffff)
at <Unknown>.ComponentManager.Interop.Mso.IMsoComponentManager.FPushMessageLoop  (IL offset: 0x147)
at <Unknown>.ThreadContext.RunMessageLoopInner  (IL offset: 0x1a4)
at <Unknown>.ThreadContext.RunMessageLoop  (IL offset: 0x19)
at <Unknown>.Application.Run  (IL offset: 0xc)
at <Unknown>.Program.Main  (IL offset: 0xc5)
