rootPanel.add(mainMenu);
rootPanel.setWidgetPosition(mainMenu, 0, 0);
//cargo la barra de botones
MainToolBar mainToolBar = new MainToolBar();
mainToolBar.setId("main_tool_bar");
rootPanel.add(mainToolBar);
rootPanel.setWidgetPosition(mainToolBar, 0, DEFAULT_MENU_HEIGTH);
//cargo el panel tab
MainTabPanel mainTabPanel = new MainTabPanel();