Have you checked the execution plan to see what is being referenced from the query? It might not be using the view at all. Or, it's possible that, despite the construct of the view, the filtering just won't work within the view. You can tell all this from the execution plan rather than trying to guess from the code.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning