Hi!
1. Try to disable this option here: https://i.imgur.com/127nSxY.png
By default the plugin allows results that does not have any term from the filtered taxonomy to show up.
2. I think there is too much margin around the box there. I would recommend this custom CSS to reduce it on mobile devices:
[html]@media only screen and (max-width: 480px) {
.probox {
margin: 0 !important;
}
}[/html]
This looks like: https://i.imgur.com/SoBsCTA.png
3. By hitting the left arrow key on the keyboard.