nested Layouts

I would like to use the layout library to make nested menus. When i do this:

var mainMenu = new Layout( {
  {type:"btn", label:"A", cb:l=>{mainMenu.clear();AMenu.render();}­}
}
var AMenu = new Layout( {
  {type:"btn", label:"something", cb:l=>{}}
}

it shows menu "A" when i push the button, but the buttons from mainMenu are still active. Is there a simple way to completely remove a layout from screen?
Also, i would like to change a value via the graphical menu, but without actually displaying the menu. Is there a way to do this? I could just use the menu interface, but it is difficult to use wearing gloves.