void makeTransparent(Component component,int alpha) {
    	component.setBackground(changeAlpha(component.getBackground(), alpha));
    	component.setForeground(changeAlpha(component.getForeground(), alpha));
    	if (component instanceof Container) {
    		Container container=(Container)component;
    		for (int i=0; i<container.getComponentCount(); ++i)
    			makeTransparent(container.getComponent(i),alpha);
    	}
    }