The DragPanel extender is one of the simplest extenders in the ACT. It has only two properties—one to indicate the panel to drag, and one to indicate the panel to use as the drag handle:
As the name suggests, the TargetControlID property refers to the ID of the panel control in the page that is going to be moved. The DragHandleID, on the other hand, indicates the ID of the panel control that is used as the handle of the drag. In other words, to drag the target panel users drag and drop the handle panel. Although functionally distinct, the two panels are, in effect, logically correlated and rendered through nested tags:
The target panel usually contains as a child the drag handle panel. In this way, you obtain the effect of moving the whole panel as if it were a Microsoft Windows window.