Bottom and selection summary shows "3 folders (2 hidden)"
Summary shows "3 folders" but the folders aren't visible, so might be confusing for users.
This happens with files as well.
Another possible confusion:
As a user, I'd expect the "select all" checkbox to go off since I deselected everything. But since there are hidden files still selected, it doesn't behave that way.
One idea I had: besides adding "X hidden entries" in the summary, also add it in the selection summary and make it clickable. When clicked, it will temporarily toggle displaying the hidden files.