satchmo_store.shop.context_processors.settings set context variable with very generic names such as "categories".
When using satchmo with an other application (in my case django-helpdesk) that internally use categories variable name (in this case for it's own knowledge base categories).
Satchmo overwrite categories.
When context processors are applied
When you use RequestContext, the variables you supply directly are added first, followed any variables supplied by context processors. This means that a context processor may overwrite a variable you've supplied, so take care to avoid variable names which overlap with those supplied by your context processors.