Trouble with filter involving multiple tables

I'm hoping I'm missing something rudimentary on this one.

I have several tables relating Features, and the Vehicles and Displays that those features support. I also have a table showing what displays each vehicle supports:

I'd like to create a Matrix visualization to produce something like this:

This is my matrix setup:

And my measure:

Feature Exists = 
var _Feature = SELECTEDVALUE(Features[Feature ID])
var _Display = SELECTEDVALUE(Displays[Display ID])

return
CALCULATE(
    IF(_Feature in VALUES('Displays to Features'[Feature ID])
        ,"X"
    ),
    FILTER('Displays to Features',
    'Displays to Features'[Display ID] = _Display
    ),
)

Without the filter at the end, the Matrix will show me what Features are on what vehicle, like this, with the Displays row blank:

And with the Filter, the Matrix is completely empty. Do I need to do anything special because I'm using the selected value from one filter path to filter another related table?

Thank you!