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). 

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;
}

Great Search addon, but .. a litle Bug? Rated 5 out of 5 stars

This is a great add on. The default search in Thunderbird is too complicated. Too many buttons and clicks. Expression Search makes it as I would like the search to be. But something doesn't work very well. Once every 2 times when I click <CTRL-Enter> I go to the default thunderbird search. How can I avoid this??

edit:
-----
Once every 2 times, It does not create a virtual folder but it does the search as default in thunderbird (it opens a new tab with the search results and the possibility to filter the search (not for me, for me etc.., people etc)).
I hope I made myself clear.

This review is for a previous version of the add-on (0.8.4). 

please describe in more details, like: OS version, TB version, addon version, how to reproduce etc.
Do you see any error log in 'Tools'/'Error Console"?