You also mentioned using “Lyo Designer 4.0.0 m1”. Can I ask how you downloaded this particular version? The official released version of Lyo Designer is 2.4.0. And we also have the latest snapshot downloadable as instruncted under https://oslc.github.io/developing-oslc-applications/eclipse_lyo/install-lyo-designer.html.
But not 4.0.0 m1.