searchBack_btn.setMargin( btn_insets );
searchBack_btn.setToolTipText( "Search Backward in time" );
searchBack_btn.setMnemonic( KeyEvent.VK_B );
// searchBack_btn.setPreferredSize( btn_dim );
searchBack_btn.addActionListener(
new ActionSearchBackward( this, canvas_vport ) );
super.add( searchBack_btn );
icon_URL = getURL( Const.IMG_PATH + "Find24.gif" );
if ( icon_URL != null )
searchInit_btn = new JButton( new ImageIcon( icon_URL ) );