I'm hoping someone can help me fill in the gaps in my understanding of page templates and query vars:
I've registered a custom taxonomy 'stream', and have set up a page template for that taxonomy, taxonomy-stream.php. The page template lists an archive of posts that are using the respective taxonomy term. Everything there works fine.
I'm trying to add a filter to the sidebar to allow the user to narrow down the taxonomy archive of posts based on Categories. I am finding that if I add a query var to the URL (?category_name=text, for example) that the page template switches from my taxonomy-stream.php template to archive.php. My goal, however, is for the ?category_name=test query var to limit the results of the taxonomy archive.
The query var itself seems to be changing the page template to archive.php instead of keeping it on the taxonomy-stream.php template. What am I missing here?