NPE when saving multiple domain models on identical name

[Former user]

Application crashes with a NPE when two domain models are created under identical name and one then tries to delete one.

Exception in thread "Animation Thread" java.lang.RuntimeException: java.lang.NullPointerException at com.jogamp.common.util.awt.AWTEDTExecutor.invoke(AWTEDTExecutor.java:58) at jogamp.opengl.awt.AWTThreadingPlugin.invokeOnOpenGLThread(AWTThreadingPlugin.java:103) at jogamp.opengl.ThreadingImpl.invokeOnOpenGLThread(ThreadingImpl.java:206) at javax.media.opengl.Threading.invokeOnOpenGLThread(Threading.java:172) at javax.media.opengl.Threading.invoke(Threading.java:191) at javax.media.opengl.awt.GLCanvas.display(GLCanvas.java:541) at processing.opengl.PJOGL.requestDraw(PJOGL.java:688) at processing.opengl.PGraphicsOpenGL.requestDraw(PGraphicsOpenGL.java:1651) at processing.core.PApplet.run(PApplet.java:2256) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: java.lang.NullPointerException at ca.mcgill.sel.ram.ui.views.structural.BaseView.<init>(BaseView.java:116) at ca.mcgill.sel.ram.ui.views.structural.ClassifierView.<init>(ClassifierView.java:138) at ca.mcgill.sel.ram.ui.views.structural.ClassifierView.<init>(ClassifierView.java:172) at ca.mcgill.sel.ram.ui.views.structural.ClassView.<init>(ClassView.java:60) at ca.mcgill.sel.ram.ui.views.structural.StructuralDiagramView.addClass(StructuralDiagramView.java:229) at ca.mcgill.sel.ram.ui.views.structural.StructuralDiagramView.handleNotification(StructuralDiagramView.java:495) at ca.mcgill.sel.ram.ui.components.listeners.UINotifyChangedListener$1.run(UINotifyChangedListener.java:24) at org.mt4j.AbstractMTApplication.runApplication(AbstractMTApplication.java:360) at org.mt4j.AbstractMTApplication.draw(AbstractMTApplication.java:272) at processing.core.PApplet.handleDraw(PApplet.java:2386)