Lee was detained by Immigration and Customs Enforcement in Louisiana (part of the Tenth Circuit), but his case was heard via televideo equipment by an Immigration Judge in Dallas, Texas (part of the Fifth Circuit). Lee was physically transported to Dallas for his final hearing. When his case was denied by both Immigration Judge and the Board of Immigration Appeals, Lee filed a Petition for Review with the Fifth Circuit. The Fifth Circuit summarily transferred the Petition for Review to the Tenth Circuit, who in today's decision, transferred it back, finding that the proper venue in a detention case is the jurisdiction in which the Immigration Judge sits, rather than the jurisdiction in which the detention center resides.
The full text of Lee v. Holder can be found here: http://www.ca10.uscourts.gov/opinions/14/14-9573.pdf