Select all option should be visible in the slicers (When a users searches anything)

What is the existing feature?

Right now, a slicer tool offers a "Select all" check box along with the "Search" feature.

What is the problem?

If a user searches for any key, the slicer shows all the matching results. But the "select all" option disappears.

Due to this, the user has to multi-select all the items that match the search key. If it is a long list, it's a big pain.

What might be the solution?

The "Select all" option should be available on top of the slicer (Just like the "search"). If the user searches for particular items and he wants to select everything that matches the search key.