--- a/Implab/AbstractEvent.cs	Sat Apr 16 03:23:26 2016 +0300
+++ b/Implab/AbstractEvent.cs	Mon Apr 18 16:41:17 2016 +0300
@@ -77,18 +77,19 @@
         /// <param name="error">Исключение возникшее при выполнении операции</param>
         /// <exception cref="InvalidOperationException">Данное обещание уже выполнено</exception>
         protected void SetError(Exception error) {
+            while (error is PromiseTransientException)
+                error = error.InnerException;
+
+            var isCancel = error is OperationCanceledException;
+            
             if (BeginTransit()) {
-                if (error is OperationCanceledException) {
-                    m_error = error.InnerException;
-                    CompleteTransit(CANCELLED_STATE);
-                } else {
-                    m_error = error is PromiseTransientException ? error.InnerException : error;
-                    CompleteTransit(REJECTED_STATE);
-                }
+                m_error = isCancel ? error.InnerException : error;
+                CompleteTransit(isCancel ? CANCELLED_STATE : REJECTED_STATE);
+
                 Signal();
             } else {
                 WaitTransition();
-                if (m_state == SUCCEEDED_STATE)
+                if (!isCancel || m_state == SUCCEEDED_STATE)
                     throw new InvalidOperationException("The promise is already resolved");
             }
         }