I published the beta build last week for an update to the Extended Events Manager that made a performance enhancement to the TargetDataViewer in the Library to make it work on a background worker thread to prevent UI freezing while the data is pulled, improving performance while reading target data from the asynchronous_file_target. Included in the update is the addition of an SSMS Addin that eliminates the need for an external UI, implementing the application functionality entirely in SQL Server Management Studio. So far the SSMS Addin has been successful without bugs being reported. To download the new version of the application see the following link:
http://extendedeventmanager.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=30480