Design view of node js layout going blank white

Hello there, I am very new to Wappler, only a few days in after switching from Oxygen builder on WordPress. I am using nodejs trying to create a dashboard.

When editing a layout page which contains top nav and sidebar, the design view goes blank. I have to restart Wappler to get it back.

When I open a content page in Wappler in the browser it works perfectly. All is as expected.

Is it something I have done wrong? Or have I missed something?

I would greatly appreciate your help.

Thanks, and sorry for the video quality.