The Chron reported this morning that it is joining two other publications, Bloomberg News and the legal newspaper The Recorder, in seeking the unsealing of documents related to back-dated stock options at Mercury Interactive, a Mountain View business software company. The three media outlets have filed court papers to unseal documents Mercury provided in the shareholder lawsuit under a confidentiality order. They say the documents might reveal the inside story on how backdating occurred. Ironically, the Hearst Corp., the Chron’s owner, and MediaNews Group are fighting an attempt by the San Francisco Bay Guardian and the nonprofit Media Alliance to unseal records in Clint Reilly’s lawsuit against the two newspaper chains. Hearst and MediaNews in September convinced U.S. District Judge Susan Illston to issue a confidentiality order sealing all documents in the case that weren’t already public record.