Inherit UserFriendlyException from ApplicationException instead of AbpException.

src/Volo.Abp.UI/Volo/Abp/Ui/IUserFriendlyException.cs

@@ -1,5 +1,9 @@
 namespace Volo.Abp.Ui
 {
+    /* TODO:
+     * - define an interface to split Details, like IHasExceptionDetails
+     */
+
     public interface IUserFriendlyException
     {
         string Message { get; }

src/Volo.Abp.UI/Volo/Abp/Ui/UserFriendlyException.cs

@@ -9,7 +9,7 @@ namespace Volo.Abp.Ui
     /// This exception type is directly shown to the user.
     /// </summary>
     [Serializable]
-    public class UserFriendlyException : AbpException, IHasLogLevel, IHasErrorCode, IUserFriendlyException
+    public class UserFriendlyException : ApplicationException, IHasLogLevel, IHasErrorCode, IUserFriendlyException
     {
         /// <summary>
         /// Additional information about the exception.