Seattle-based real estate site Redfin, which is headed by Glenn Kelman, is facing a patent lawsuit in Texas over the company's new Home Price Tool. According to the lawsuit, from real estate information provider CoreLogic, CoreLogic says that Redfin is infringing on U.S. Patent No. 5,361,201, covering real estate appraisal using predictive modeling. The lawsuit was filed in the Texas Eastern District Court. Redfin launched its new home price tool in March. The suit was first uncovered by Geekwire.