Taiob Ali points out a bug in SQL Server Management Studio:
SQL Server Management Studio (SSMS) showplan root node properties have two attributes to indicate when a filtered index can not be used during a parameterized query. One is ‘UnmatchedIndexes’, and the other one is under ‘Warnings’ attribute. Due to a bug in SSMS, the attributes are also showing positive results with filtered index and non-parameterized queries.
Let’s look at an example. I am using the AdventureWorks database, which you download from here.
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