WebPartZoneBase.RenderDropCue Method (HtmlTextWriter)
Renders user interface (UI) elements to indicate to an end user where a WebPart control that is being dragged can be dropped within a zone.
Assembly: System.Web (in System.Web.dll)
If a page is in design display mode, and the AllowLayoutChange property is set to true (the default), users can change a page's layout by dragging WebPart controls within and between zones. The method renders UI elements, depending on the LayoutOrientation property of the zone, that indicate to users where a control that is being dragged can be dropped.
Available since 2.0