Here a new tip for you on filtering. Have you ever wanted to eliminate a Null from you filter but when you click back on ‘All’ the ‘unwanted item’ comes back again?

The only way to eliminate this problem is to create a new set. If your value is a measure you must then make a copy and drag it to dimension and then create a new set. You then drag it to filter and you have your filter fixed. Here a video to better understand this: