SUMMARY for me, one of the most useful features of okular is the filter bar in the thumbnail pane. the dropdown menu with filter options on the right of the filter bar is also useful, but it would be more convenient to have a "triger button" which would show/hide the filter options between the filter bar and the thumbnails. this way, it could choose to always have the selected options visible (in practice I often find my self having to verify whether I have "match phrase" or "match all words" selected).