Custom Project view: last path component must be non-null

[arimer]

java.lang.IllegalArgumentException: Last path component must be non-null
    at java.desktop/javax.swing.tree.TreePath.<init>(TreePath.java:106)
    at jetbrains.mps.ide.ui.tree.MPSTree.getExpandedPathsRaw(MPSTree.java:777)
    at com.mbeddr.mpsutil.projectview.runtime.tree.CustomProjectView.saveExpandedPaths(CustomProjectView.java:544)
    at com.mbeddr.mpsutil.projectview.runtime.tree.CustomProjectView.rebuild(CustomProjectView.java:523)
    at com.mbeddr.mpsutil.projectview.runtime.tree.CustomProjectView$MyRepositoryListener.rebuildTreeIfNeeded(CustomProjectView.java:877)
    at com.mbeddr.mpsutil.projectview.runtime.tree.CustomProjectView$MyRepositoryListener.commandFinished(CustomProjectView.java:916)
    at java.base/java.util.concurrent.CopyOnWriteArrayList.forEach(CopyOnWriteArrayList.java:807)
    at jetbrains.mps.smodel.ActionDispatcher.onExit(ActionDispatcher.java:222)
    at jetbrains.mps.smodel.ActionDispatcher.dispatch(ActionDispatcher.java:114)
    at jetbrains.mps.smodel.ActionDispatcher.lambda$wrap$0(ActionDispatcher.java:135)
    at jetbrains.mps.smodel.ActionDispatcher.dispatch(ActionDispatcher.java:98)
    at jetbrains.mps.smodel.ActionDispatcher.lambda$wrap$0(ActionDispatcher.java:135)
    at jetbrains.mps.smodel.LockRunnable.run(LockRunnable.java:60)
    at jetbrains.mps.smodel.TryRunPlatformWriteHelper.lambda$tryWrite$2(TryRunPlatformWriteHelper.java:122)
    at com.intellij.openapi.application.impl.ApplicationImpl.runWriteAction(ApplicationImpl.java:1023)
    at jetbrains.mps.smodel.TryRunPlatformWriteHelper.runWrite(TryRunPlatformWriteHelper.java:103)
    at jetbrains.mps.smodel.TryRunPlatformWriteHelper.tryWrite(TryRunPlatformWriteHelper.java:120)
    at jetbrains.mps.smodel.WorkbenchModelAccess.lambda$tryWriteInCommand$3(WorkbenchModelAccess.java:218)
    at jetbrains.mps.util.ComputeRunnable.compute(ComputeRunnable.java:32)
    at jetbrains.mps.util.AbstractComputeRunnable.run(AbstractComputeRunnable.java:27)
    at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:219)
    at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:174)
    at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:164)
    at jetbrains.mps.smodel.WorkbenchModelAccess.tryWriteInCommand(WorkbenchModelAccess.java:235)
    at jetbrains.mps.smodel.WorkbenchModelAccess.lambda$runCommandInEDT_$2(WorkbenchModelAccess.java:151)
    at jetbrains.mps.smodel.EDTExecutor$1.tryRun(EDTExecutor.java:61)
    at jetbrains.mps.smodel.EDTExecutorInternal.tryToRunTopTask(EDTExecutorInternal.java:296)
    at jetbrains.mps.smodel.EDTExecutorInternal.flushNTasks(EDTExecutorInternal.java:251)
    at jetbrains.mps.smodel.EDTExecutorInternal.doFlush(EDTExecutorInternal.java:233)
    at jetbrains.mps.smodel.EDTExecutorInternal.flushTasksQueue(EDTExecutorInternal.java:213)
    at jetbrains.mps.smodel.EDTExecutorInternal.lambda$guaranteeWriteSafetyViaHack$2(EDTExecutorInternal.java:200)
    at com.intellij.openapi.application.TransactionGuardImpl.runWithWritingAllowed(TransactionGuardImpl.java:209)
    at com.intellij.openapi.application.TransactionGuardImpl.access$100(TransactionGuardImpl.java:21)
    at com.intellij.openapi.application.TransactionGuardImpl$1.run(TransactionGuardImpl.java:191)
    at jetbrains.mps.smodel.EDTExecutorInternal.lambda$guaranteeWriteSafetyViaHack$3(EDTExecutorInternal.java:205)
    at jetbrains.mps.smodel.EDTExecutorInternal.lambda$forceScheduleFlushEDT$1(EDTExecutorInternal.java:168)
    at com.intellij.openapi.application.TransactionGuardImpl$1.run(TransactionGuardImpl.java:194)
    at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:881)
    at com.intellij.openapi.application.impl.ApplicationImpl$3.run(ApplicationImpl.java:513)
    at com.intellij.openapi.application.impl.FlushQueue.doRun(FlushQueue.java:75)
    at com.intellij.openapi.application.impl.FlushQueue.runNextEvent(FlushQueue.java:118)
    at com.intellij.openapi.application.impl.FlushQueue.flushNow(FlushQueue.java:42)
    at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:318)
    at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:779)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:730)
    at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:724)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:749)
    at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:918)
    at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:766)
    at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$6(IdeEventQueue.java:450)
    at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:791)
    at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$7(IdeEventQueue.java:449)
    at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:105)
    at com.intellij.ide.IdeEventQueue.performActivity(IdeEventQueue.java:624)
    at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:447)
    at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:881)
    at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:493)
    at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:207)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:92)