mainTabPanel.setId("main_tab_panel");
rootPanel.add(mainTabPanel);
rootPanel.setWidgetPosition(mainTabPanel, 0, new Integer(2*DEFAULT_MENU_HEIGTH));
//cargo la barra de estado
MainStatusBar mainStatusBar = new MainStatusBar();
mainStatusBar.setId("main_status_bar");
rootPanel.add(mainStatusBar);
rootPanel.setWidgetPosition(mainStatusBar, 0, new Integer((2*DEFAULT_MENU_HEIGTH) + MAIN_TAB_PANEL_HEIGTH));
}