v23 keeps having nullpointerexception on startup

After i build my project and start it for the 2nd time on that build, i get a nullpointerexception on the MainLayout page. And when i do a mvn clean and a new build, it works again…

Does it give you an NPE on subsequent starts? If it does, please provide more context: the source code for the layout and the stack trace, so we can better help