Is anyone else getting this error when attempting to delete a coupon from an order on the shopping cart page?

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Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientscriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.



Descript<b>ion:</b> An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.



Exception Details: System.ArgumentException: Invalid postback or callback argument. Event validation is enabled using &lt;pages enableEventValidation="true"/&gt; in configuration or &lt;%@ Page EnableEventValidation="true" %&gt; in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientscriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.



Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.



Stack Trace:


[ArgumentException: Invalid postback or callback argument. Event validation is enabled using &lt;pages enableEventValidation="true"/&gt; in configuration or &lt;%@ Page EnableEventValidation="true" %&gt; in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientscriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.]
System.Web.UI.ClientscriptManager.ValidateEvent(String uniqueId, String argument) +8623897
System.Web.UI.Control.ValidateEvent(String uniqueID, String eventArgument) +72
System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +35
System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

I just tested it with 5.7.3 and did not get an error. It could be that one of the products in your cart has some HTML in its name or one of its choices which may be causing the ASP.NET event validation to trip. Try another product and see if you still get an error.

Could be an EnableViewstate setting on one of the controls...