To Jason: Had emergency trip out of state. Am back now.
More Info: I only rcv. the mouseup error in sites that were built and defined with DW CS3 and "imported" into DW CS4. Sites made and defined with DW MX2004 and "imported" into DW CS4 work fine with the Validation extension. I have rebuilt the sites that do not work with the extension in DW CS4 but to no avail. The Web Standards extension simply will not work with my sites. Can you say ANNOYING? I am sure there is a fix but I can't, and don't have the spare time to keep experimenting but would sure like my INVESTMENT to work as designed.. Bob