In the January 2017 release it looks like the Search facility on a slicer that is set to a drop down has been removed? I can set up a slicer as list and search it but as soon as I switch it to a...
It must have come back because we figured it out at some point and shared this "how to" with our users (of course the best UX would not require a "how to", but no one could find this hidden search function - it's a lot of clicks): https://drive.google.com/open?id=13zp9l2o0YsQ88Nz8C2gEMSXO61iowv35