the undo/redo option are, for some reason, no longer working in mps...

has this ever happened to anyone else?

if yes, is there a quick fix?

Was the focus in the opened editor before you opened the main menu? Are the changes on the picture are “fresh”?

Yes, all changes are up to date. One thing that might be causing this is having open two projects at the same time. But even so, editing fails for both

Yes, working with 2 projects opened might cause problems. We suggest to have 1 opened project.

it's the same for one project as well

Well, I can’t find why undo doesn’t work in you case. What is your OS and MPS version? Maybe could catch the problem while checking specific versions.

Slack user:U6M94JMGX> Looking at:

it might be related to an iets3 plugin. In our case, however, we cannot remove it from the project.

this happens on startup

```Error executing task de.audi.rcp.plugin.plugin.IDefXUpdateCheckerPlugin_ProjectPluginPart$1$1@17c31094 jetbrains.mps.classloading.ModuleClassLoader$ModuleClassLoaderIsDisposedException: ClassLoader of the module 'de.audi.rcp.plugin [solution]' is disposed and not operable! at jetbrains.mps.classloading.ModuleClassLoader.checkNotDisposed(ModuleClassLoader.java:92) at jetbrains.mps.classloading.ModuleClassLoader.loadClass(ModuleClassLoader.java:121) at jetbrains.mps.classloading.ModuleClassLoader.loadClass(ModuleClassLoader.java:117) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) at de.audi.rcp.plugin.plugin.IDefXUpdateCheckerPlugin_ProjectPluginPart$1$1.run(IDefXUpdateCheckerPlugin_ProjectPluginPart.java:31) at com.intellij.openapi.project.DumbServiceImpl.doRun(DumbServiceImpl.java:403) at com.intellij.openapi.project.DumbServiceImpl.updateFinished(DumbServiceImpl.java:395) at com.intellij.openapi.project.TrackedEdtActivityService$TrackedEdtActivity.run(TrackedEdtActivityService.java:66) at com.intellij.openapi.application.TransactionGuardImpl.runWithWritingAllowed(TransactionGuardImpl.java:218) at com.intellij.openapi.application.TransactionGuardImpl.access$200(TransactionGuardImpl.java:21) at com.intellij.openapi.application.TransactionGuardImpl$2.run(TransactionGuardImpl.java:200) at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:781) at com.intellij.openapi.application.impl.ApplicationImpl.lambda$invokeLater$4(ApplicationImpl.java:319) at com.intellij.openapi.application.impl.FlushQueue.doRun(FlushQueue.java:84) at com.intellij.openapi.application.impl.FlushQueue.runNextEvent(FlushQueue.java:133) at com.intellij.openapi.application.impl.FlushQueue.flushNow(FlushQueue.java:46) at com.intellij.openapi.application.impl.FlushQueue$FlushNow.run(FlushQueue.java:189) at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313) at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:776) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:727) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:746) at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:969) at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:839) at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:449) at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:808) at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$9(IdeEventQueue.java:448) at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:781) at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:496) at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)```

In case of Noli we discovered it was caused by incompatible versions of MPS and IETS plugins. There was the same AssertionError stacktrace as in https://youtrack.jetbrains.com/issue/MPS-34348. Are your versions compatible?