Provides a Swing marker bar for a Java application. A marker bar is a stripe containing markers that indicate where objects fall within a document.

Developers wishing to add a marker bar to their applications need to do three things.

1. Define a javax.swing.ListModel of Marker objects. Each Marker states its percentage along the marker bar (e.g. 0.25 to 0.29).
2. Instantiate a JMarkerBar, passing it the ListModel, and add it to the window.
3. Register an action listener with the marker bar to define what happens when the user clicks on a marker.

@serial exclude