Help. HorizontalLayout expandRatio

I’m having issue with how to correctly sizing component in HorizontalLayout (menu example). It overflows the area when initially rendered. (Dashboard menu example) as in screenshot attached.

When I click on the menu Item to re-render view or resize window - component gets correct size.
This happend when setExandRatio( content, 1.0f); which is default in left Menu implementation.

Can someone shed the light how this suppose to work please?

Example project:

Component Expand issue