Content of the layout. There can only be one top-level LayoutItem in the content array.
We do not recommend trying to build Layouts or LayoutItems by hand and instead use calls such as getSnapshot.
Whether to show the popout button on stack header.
The button will create a new window with current tab as its content.
In case popoutWholeStack is set to true, all tabs in the stack will be in the new window.
Content of the layout. There can only be one top-level LayoutItem in the content array. We do not recommend trying to build Layouts or LayoutItems by hand and instead use calls such as getSnapshot.