Hi Paul J,
I just answered your support ticket on the same subject. For convenience I am pasting my reply below.
This behavior is expected - it is the way RadFormDecorator works.The research that we did, when we started working on RadFormDecorator, show that from a customers' point of view, it is better to have all elements (that can be decorated) initially hidden and then, when the decoration mechanism finish its work, shown on the page at the same time. In the other case, users will see "flickering" in the parts of the page where the decorator styles the controls. For example, if you have a page full of columns with checkboxes and you want to decorate only the first column, once the page is loaded, the users will see how the first column flickers while being decorated. The showing of the decorated controls can indeed be slow during the initial load because in ASP.NET AJAX, the Ajax controls (including ours) are created and initialized after the page has been loaded (in Sys.Application.Load). This delay is more visible on pages with a lot of controls on them - our RadFormDecorator demos do not have many controls on the same page and that is why the loading there seems fast.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items