Display all in a filter

Anonymous you need to add a row in your slicer table with value all and then choose sort order in a way that it shows up on the top. Also in your measures and everywhere, you need to make sure all selection is doing what it is expected to do. There is nothing out of the box for single select.

Anonymous 

You may take a look at the following posts.

• https://community.powerbi.com/t5/Desktop/Tricky-Slicer-Options/m-p/573381#M270846
• https://community.powerbi.com/t5/Desktop/Use-a-date-slicer-to-filter-on-a-period-instead-of-a-single-date/m-p/588265#M278953