Invoking the remedy that Section 12.56(a)(3) of the Illinois Business Corporation Act provides for minority shareholders victimized by “oppressive” conduct — a term that isn’t precisely defined by Illinois precedent — David Vanco sued Chicago Flameproof & Wood Specialties Corp. and its controlling shareholders (president-for-life Vincent Mancini and vice-president Maddy Rossobillo). Mancini allegedly diluted Vanco’s ownership interest from 16% to 5%; gave “better terms” to “favored minority shareholders” on a …