In previous version of WebUI.NET Framework, the viewstate size of a control is relatively large since it is using BinarySerialization to serialize the entire control. While the size issue is not significant when saved to server-side storage, it introduced barrier when saved to Client.
In this new version, we have enhanced the ViewStateStorage feature using new OptimizedState architecture that based on "Delta changes". The viewstate size of a control now has been reduced significantly (approximately 60 percent smaller) and thus, allow ViewStateStorage to be saved to Client (as in standard .NET controls).
In 2007 R1, we have also improved the ViewStateStorage implementation when saved to PageCache option. Although the default ViewStateStorage in this new version is set to Client, you can now safely change it back to PageCache if required. The memory allocation required by the PageCache implementation has been optimized by 70 percent. The new PageCache implementation has also been improved to avoid memory leaks.