SSRS Subscriptions and Blank Labels

Ran into an interesting issue with SSRS subscriptions. Actually, I am very surprised I have not run into this yet.

I am running SQL Server 2008r2 SP1.

If you have a report with a multi select parameter that allows blanks, a blank label will either prevent you from setting up the subscription, or cause the subscription to fail when it is run.

The Javascript error is:

Message: 'firstChild' is null or not an object
Line: 640
Char: 13
Code: 0
URI: http://Server/InternalReporting/js/ReportingServices.js

and the subscription error is:

Failure sending mail: Default value or value provided for the report parameter 'ReportParameter1' is not a valid value. Mail will not be resent.

I have opened an issue on Connect:  http://connect.microsoft.com/SQLServer/feedback/details/750927/blank-parameter-labels-cause-error-in-subscriptions

What I have done in the meantime is to replace any blank labels with a holder character ("-").

Has anyone else ran into this issue?

BobP