Update/Progress Control in Gaia

An Update or Progress Control is something that's only visible while the framework is going server-side to do some logic. (in a Gaia Callback)
You can set only ONE Update control for your page, but if you have set one Update control this control will be used every time an Ajax Callback is being issued.
In this example when you click the Ajax Button or in any other ways creates an Ajax Callback the Update Control will be made visible, and ONLY then. You can use ANY Gaia Control you wish to use as an Update Control, though probably the only ones that makes any sense is the Gaia Panel or the Gaia Window. It probably also doesn't make much sense to have a lot of "complex controls" inside your Update Control since the behaviour will be quite undefined if you add too much logic to your Update Control. We normally don't encourage users to have ANYTHING else than just a Label (or several) or some static text within the control. Perhaps if you'd like to be able to reuse the Update Control then you might consider using a UserControl or some of a sort.

Please wait while Ajax Request is in progress......

This label will be updated when you click the button, note that we've intentionally added up a 2 seconds DELAY on the server-side to be able to SEE the Update Control in 'action'

Label updated when DropDownList goes server-side...!