When I swipe (with Swype) a name, Textra can't find the matching group because Swype adds a final space character (as a separator) and Textra can't find the group when the search string has a space at the end. Oddly, it can find an individual's name with an extra space at the end - just not a group.
That should be fixed, but maybe you could add: if there are no matches, show "fuzzy" matches, maybe in a different font or color. Maybe add a checkbox to temporarily enable fuzzy search at any time.
Also, maybe add a check box to temporarily allow searching contacts w/o mobile numbers (if the setting disallowing that is enabled).