Great upgrade! Rated 5 out of 5 stars

Thank you for your great upgrade.
Much much better now. It is better as the default thunderbird search. Like also the regex search (never seen it before, maybe it was there before). How do I drag the expression search bar to my own toolbar (I created). I wish also to hide the icons, unread, starred, contact, tags, attachment. Thanks again for your great work!

This review is for a previous version of the add-on (0.8.5).  This user has a previous review of this add-on.

In the addon's settings dialog, you can choose to move the search bar to menu bar or toolbar, but can't move to user defined toolbar.

Also in current design, there's no option to hide the icons, it's moved along with search bar. But you can do it by userChrome.css (https://developer.mozilla.org/en-US/docs/Thunderbird/Thunderbird_Configuration_Files), eg, add the following lines:
#quick-filter-bar-collapsible-buttons {
display: none !important;
}
If you also like to hide the sticky button, use:
#qfb-sticky , #quick-filter-bar-collapsible-buttons {
display: none !important;
}