When the mouse pointer is over the "event" or "date" word, ASPxHint is shown with ASPxListBox or ASPxCalendar inside.
Every time ASPxHint is shown, a callback is sent to the server to get the control's rendering. The ASPxCallback control is used to send callbacks.The ASPxCallback.GetRenderResult method passes this rendering to the client side.
The page hierarchy is restored using ASPxHiddenField in the Page_Init event handler. It allows server-side controls to work using internal callbacks (for example, ASPxListbox loads items "on demand" using callbacks).
Files to look at:• Default.aspx (VB: Default.aspx)
• Default.aspx.cs (VB: Default.aspx.vb)