lib/Ext/navigation/Bar.js
function(element) {
        var ghost, x, y, left, width;

        ghost = element.dom.cloneNode(true);
        ghost.id = element.id + '-proxy';

        //insert it into the toolbar
        element.getParent().dom.appendChild(ghost);

        //set the x/y
        ghost = Ext.get(ghost);
        x = element.getX();
        y = element.getY();
        left = element.getLeft();
        width = element.getWidth();
        ghost.setStyle('position', 'absolute');
        ghost.setX(x);
        ghost.setY(y);
        ghost.setHeight(element.getHeight());
        ghost.setWidth(width);

        return {
            x: x,
            y: y,
            left: left,
            width: width,
            ghost: ghost
        };
    }
function(element) {
        var ghost, x, y, left, width;

        ghost = element.dom.cloneNode(true);
        ghost.id = element.id + '-proxy';

        //insert it into the toolbar
        element.getParent().dom.appendChild(ghost);

        //set the x/y
        ghost = Ext.get(ghost);
        x = element.getX();
        y = element.getY();
        left = element.getLeft();
        width = element.getWidth();
        ghost.setStyle('position', 'absolute');
        ghost.setX(x);
        ghost.setY(y);
        ghost.setHeight(element.getHeight());
        ghost.setWidth(width);

        return {
            x: x,
            y: y,
            left: left,
            width: width,
            ghost: ghost
        };
    }
Creates a proxy element of the passed element, and positions it in the same position, using absolute positioning.
The createNavigationBarProxy method uses this to create proxies of the backButton and the title elements.
@private