RegisterClientScriptBlock() incompatibility in .Net v2.0 Beta 1 – level 100

This may impact many people because it is a change in the validation of the parameters of this method.  The method is defined below:

RegisterClientScriptBlock(string key, string script);

In .Net 1.1, the key parameter could not be null, but it COULD be a zero-length string.  In .Net 2.0 Beta 1, this parameter is validated so that an empty string is not valid input.  It throws an exception. 

Maybe a validation change for the better, but a breaking change none-the-less.