Flutter Inspector closed and doesn't open again

Please file this bug report at https://github.com/flutter/flutter-intellij/issues/new.

---

## What happened

My flutter inspector isn't working well for quite some time, specially after I upgraded to the new UI. I have multiple emulators, real devices and ios simultor running at the same time. This time Flutter inspector just showed a black frame and the IDE showed an error.

Please dedicate some time to make it work reliably, this is an essential tool and ultimately it only works if I close everything and rebuilds the app.

I am on a Mac M2 Pro.

## Version information

Android Studio `Giraffe | 2022.3.1 Patch 1` • Flutter plugin `io.flutter 75.1.2` • Dart plugin `223.8950`

Flutter 3.13.4 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 367f9ea16b (2 weeks ago) • 2023-09-12 23:27:53 -0500
Engine • revision 9064459a8b
Tools • Dart 3.1.2 • DevTools 2.25.0

## Exception

null

```
java.lang.NullPointerException: Cannot invoke "com.intellij.ui.content.impl.ContentImpl.setManager(com.intellij.ui.content.ContentManager)" because "content" is null
at com.intellij.ui.content.impl.ContentManagerImpl.doAddContent(ContentManagerImpl.java:194)
at com.intellij.ui.content.impl.ContentManagerImpl.addContent(ContentManagerImpl.java:171)
at io.flutter.view.EmbeddedBrowser.lambda$openPanel$0(EmbeddedBrowser.java:110)
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 com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:838)
at com.intellij.openapi.application.impl.ApplicationImpl$3.run(ApplicationImpl.java:454)
at com.intellij.openapi.application.impl.FlushQueue.doRun(FlushQueue.java:74)
at com.intellij.openapi.application.impl.FlushQueue.runNextEvent(FlushQueue.java:114)
at com.intellij.openapi.application.impl.FlushQueue.flushNow(FlushQueue.java:36)
at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Unknown Source)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:909)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:756)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$5(IdeEventQueue.java:437)
at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:787)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$6(IdeEventQueue.java:436)
at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:105)
at com.intellij.ide.IdeEventQueue.performActivity(IdeEventQueue.java:615)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$7(IdeEventQueue.java:434)
at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:838)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:480)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)
```