InfoPath Dev

I have the following as the xpath for an expression box:

concat("Total: ", string(sum(@value[@alias = "_MWP"])))

@value and @alias are attributes within a repeating field, but the predicate filter condition [@alias = "_MWP"] limits it to a single instance. 

This works fine when I preview it, giving me exactly the results I want to see. 

When I try to publish it, though, I get an error saying that this is an "unsupported control binding".  Clicking on the error gives me the following message.

"Binding a non-repeating control to a repeating field or group is not supported by InfoPath Forms Services.  To fix this problem, remove the control or replace it with a repeating control, such as repeating section or table." 

Since I know that the result of the xpath statement above will always be a single node, is there a way to ignore the error and force it to publish the form? 

It actually gave me the option to ignore the errors, but it had another error if I took that option and only told me that InfoPath had encountered an error and couldn't continue.  After restarting Visual Studio, it allowed me to ignore the "error" and publish the form anyway.  It works in the browser now!  Yea!