question: public void add ( Component comp , Object constraints ) { if ( comp == null ) { throw new RuntimeException ( "Can't add null component to DockPanel" ) ; } if ( comp instanceof DockWrapper ) { Debug . error ( "DockPanel: Unexpected call to add with a DockWrapper" ) ; super . add ( comp , constraints ) ; } else { if ( constraints . equals ( BACKGROUND ) ) { background = ( JComponent ) comp ; super . add ( comp , constraints ) ; setLayer ( comp , BACKGROUND_LAYER . intValue ( ) ) ; } else if ( constraints instanceof DockConstraint ) { if ( comp instanceof JToolBar ) { JToolBar t = ( JToolBar ) comp ; t . setFloatable ( false ) ; } setConstraint ( ( JComponent ) comp , ( DockConstraint ) constraints ) ; if ( ! alreadyAdded ( comp ) ) { createDockWrapper ( ( JComponent ) comp ) ; } } else { Debug . error ( "DockPanel: Unexpected constraint: " + constraints ) ; } } }
target:  We need to handle adding the component specially. If it is the background, do one thing. Otherwise wrap it up...