Using Split Panel in USD

Hi All,

I am trying to use a Vertical Split panel in USD as described in the below 2 tutorials however it doesn't show up at all, i.e. when I open USD it shows a blank screen.

• https://neilparkhurst.com/2016/02/02/usd-spilt-panels/
• https://blogs.msdn.microsoft.com/usd/2015/11/08/using-horizontal-and-vertical-split-panels-in-unified-service-desk/

My USD configuraiton look like

The Hosted Control "Split MainPanel" is defined as a "Panel Layout" with Panel Type = "Vertical Split". If I change the type to "Standard Main Panel" then it shows correctly in USD (along with my toolbar buttons).

Any suggestion to understand what is going on?