Classes implementing this interface are able to paint their own preview thumbnail if they are
positioned inside a JScrollPane which uses ExetededScrollPaneSelector.
Although componenets which do not implement this interface can be previewed too, the advantige
of is that the component is able to paint a more sharp preview or to highlight special elements.
ExtendedScrollPaneSelector is an extended implementation of
ScrollPaneSelector which is is a little utility class that provides a means to quickly
scroll both vertically and horizontally on a single mouse click, by dragging a selection rectangle
over a "thumbnail" of the scrollPane's viewport view.