topPanel.setColor( 1f, 1f, 1f, 0.5f );
} else {
panelShown = true;
topPanel.setY( yWhenShown );
topPanel.add( tZoomer ).expandX();
tZoomer.row();
tZoomer.add( buildPanelActionButtons( topPanel, yWhenShown, yWhenHidden ) ).align( Align.right );
}
// build the bottom panel
Table bottomPanel = buildBottomPanel( npBack, width, height );