Rated 4 out of 5 stars
I really like this (on TB 3.1 so far) as I always confused the new global search with the one below.
I do really wish for a clear button (and possibly also a 'read/unread only'-button, as the current one is hidden in the QuickFilter bar and needs two clicks to activate, even if I stop using the quickfilter,
I already have a version prepared to be uploaded that includes the clear button, I only need do some tests before publish it -specially on Thunderbird 5.0-; but remember, you can press 'Esc key' twice in current version to clear the search/filter text (first 'Esc key' pressed) and the filter options (second 'Esc key') quickly.
The 'read/unread only'-button (and other quick filter options) already are available under the widget 'options menu' (last button in the widget, or pressing the 'down key' when the focus is on the widget); this options menu have two visual modes: 'menu' (default) and 'bar'; 'menu' needs you click on it (or press 'down key') to see the options; 'bar' is showed auto when you enter on the widget (you can enabled clicking on the menu first option 'convert into a horizontal bar' and restore the menu mode clicking on the 'down arrow button' on the bar); I'm thinking to set 'bar' mode the default in newer versions; in both modes, if the options popup is opened you have shortcuts to quickly enable/disable filter options: Alt+U for toggle 'unread/read-only'. You don't need use quickfilter bar at all (mm.. only there are an option not available in Unified Search Widget: quick filter per specific tags, is on my 'to-do' list).
Thanks for the feedback,