Kickoff changes asked on panel-devel. As voted, the background painting did not get in

- Strict mouse hover
- Leaving an item will unselect that item
- Leaving the viewport will unselect the selected item if was any
- Better keyboard navigation
- If no item selected, Up will select the last item, Down will select the first item
- Search improvements
- The first result becomes the selected index, if exists
- The bottom tabbar is hidden for ease of use, intuitivity and letting more room for search results