I have the same problem as described in this topic: http://www.scriptcase.net/forum_en_us/index.php?topic=4144.msg9773#msg9773
Please consider not to load the Nested Grid while loading the Master Grid page, since this will make the page loads very very slow, moreover if you have thousands records in the detail table.
My suggestion is, please add the ability to load the records in Nested Grid only when user click on the plus (+) button using Ajax. In addition this will load the master page faster, it also more makes sense to load the detail records only when users are needing it.
Please implement this solution in the next minor release since many users are complaining to me about this condition. Thank you. Looking forward to hearing from you soon.
Sincerely,
Masino Sinaga