Today I have installed Vista SP1 RTM and then tried to test DesktopX 3.49 rc. The results have surpassed all of my expectations - IT ALREADY WORKS!!! (The minor bugs are not corrected but the standalone and Sidebar gadgets, DX widgets as well as DX Builder are really works)
But there is one thing you need to do for this - adjust the UAC through Stardock Tweak Vista:
1. Press "Security" button. Then select the "Medium-low security" item into the "Overview" tab.
2. Go to "Advanced" tab and select "Silently succeed" if you are an administrator and "Silently ignore" in the other case.
The item "Programs requesting elevation must be signed and verified" must to be unchecked!
You will never see the UAC message box after these simple tweaks. However all of DX options will work correctly.
Best Regards.
P.S. Let me know if you want to have the 24-bit Vista Boot Screen and I'll talk you how I made it with TuneUp 2008 Utilities.