Joining other Lists into SharePoint DataView - troubleshooting xsl

Question

I have very similar working code. I've tried it inside an existing sharepoint generated view and a new custom page. none of the columns or lists have been renamed or have spaces. I've trippled checked the data, column names and this code. It just produces nothing.

any good way to troubleshoot xsl?

<xsl:value-of select="/dsQueryResponse/Applicant/Rows/Row[@ID = current()/@ApplicantID]/@Address"/>

to be clear Applicant is the List source we are looking up, and @ID is the key in that table I'm filtering by. @ApplicantID is the column my current view that I'm checking that against. @Address is what I'm getting back from that lookup table.

Thanks.