[BUG] JetBrains Plugin: Input area shows only 2 lines and text unreadable in Remote Development (Gateway)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using the Claude Code plugin (not the CLI) in a JetBrains Remote Development
setup via Gateway, the input area renders with a fixed height of ~2 lines and cannot
be expanded. Additionally, typed text is not readable.

A backend exception is thrown on every editor selection change:

  Assertion failed: Failed to remove listener:
  NotificationManager$registerSelectionListener$selectionListener$1
  from editor: EditorImpl[...]
      at NotificationManager.kt:95
      at GuestFileEditorManager.fireSelectionChanged (GuestFileEditorManager.kt:177)

The plugin's NotificationManager does not handle Remote Development's
GuestFileEditorManager correctly — listener registration/deregistration fails.

What Should Happen?

Input area uses available vertical space, text is readable, no listener errors.

Error Messages/Logs

[backend] java.lang.Throwable: Assertion failed: Failed to remove listener: com.anthropic.code.plugin.mcp.notifications.NotificationManager$registerSelectionListener$selectionListener$1@601a52a0from editor: EditorImpl[file:///root/projects/diagnosis_classification_aio/train.py]
    at com.intellij.openapi.diagnostic.Logger.assertTrue(Logger.java:474)
    at com.intellij.openapi.editor.impl.SelectionModelImpl.removeSelectionListener(SelectionModelImpl.java:131)
    at com.anthropic.code.plugin.mcp.notifications.NotificationManager$registerSelectionListener$2.selectionChanged(NotificationManager.kt:95)
    at com.intellij.util.messages.impl.MessageBusImplKt.invokeMethod(MessageBusImpl.kt:831)
    at com.intellij.util.messages.impl.MessageBusImplKt.invokeListener(MessageBusImpl.kt:775)
    at com.intellij.util.messages.impl.MessageBusImplKt.deliverMessage(MessageBusImpl.kt:514)
    at com.intellij.util.messages.impl.MessageBusImplKt.pumpWaiting(MessageBusImpl.kt:493)
    at com.intellij.util.messages.impl.MessageBusImplKt.access$pumpWaiting(MessageBusImpl.kt:1)
    at com.intellij.util.messages.impl.MessagePublisher.invoke(MessageBusImpl.kt:556)
    at jdk.proxy2/jdk.proxy2.$Proxy240.selectionChanged(Unknown Source)
    at com.jetbrains.rdserver.fileEditors.GuestFileEditorManager.fireSelectionChanged$lambda$1(GuestFileEditorManager.kt:177)
    at com.intellij.openapi.application.CoroutinesKt.writeIntentReadAction$lambda$0(coroutines.kt:332)
    at com.intellij.openapi.application.impl.AppImplKt$rethrowCheckedExceptions$2.invoke(appImpl.kt:126)
    at com.intellij.platform.locking.impl.NestedLocksThreadingSupport.runWriteIntentReadAction(NestedLocksThreadingSupport.kt:705)
    at com.intellij.openapi.application.impl.ApplicationImpl.runWriteIntentReadAction(ApplicationImpl.java:1214)
    at com.intellij.openapi.application.CoroutinesKt.writeIntentReadAction(coroutines.kt:332)
    at com.jetbrains.rdserver.fileEditors.GuestFileEditorManager.fireSelectionChanged(GuestFileEditorManager.kt:176)
    at com.jetbrains.rdserver.fileEditors.GuestFileEditorManager.access$fireSelectionChanged(GuestFileEditorManager.kt:93)
    at com.jetbrains.rdserver.fileEditors.GuestFileEditorManager$1$1$1.invokeSuspend(GuestFileEditorManager.kt:144)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:34)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:100)
    at com.intellij.openapi.application.TransactionGuardImpl$2.run(TransactionGuardImpl.java:221)
    at com.intellij.openapi.application.impl.NonBlockingFlushQueue.runNextEvent$lambda$4(NonBlockingFlushQueue.kt:358)
    at com.intellij.concurrency.ThreadContext.resetThreadContext(threadContext.kt:294)
    at com.intellij.openapi.application.impl.NonBlockingFlushQueue.runNextEvent(NonBlockingFlushQueue.kt:357)
    at com.intellij.openapi.application.impl.NonBlockingFlushQueue.flushNow(NonBlockingFlushQueue.kt:305)
    at com.intellij.openapi.application.impl.NonBlockingFlushQueue.FLUSH_NOW$lambda$0(NonBlockingFlushQueue.kt:167)
    at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:323)
    at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:732)
    at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:711)
    at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.kt:721)
    at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.kt:574)
    at com.intellij.ide.IdeEventQueue.dispatchEvent$lambda$0$0$0(IdeEventQueue.kt:378)
    at com.intellij.ide.IdeEventQueueKt.performActivity$lambda$0(IdeEventQueue.kt:1111)
    at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:106)
    at com.intellij.ide.IdeEventQueueKt.performActivity(IdeEventQueue.kt:1111)
    at com.intellij.ide.IdeEventQueue.dispatchEvent$lambda$0(IdeEventQueue.kt:376)
    at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.kt:416)
    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)

Steps to Reproduce

1. Connect to a remote Linux server via JetBrains Gateway
2. Open PyCharm Professional 2026.1.2 in Remote Development mode
3. Open the Claude Code plugin tool window
4. Open any file and change the editor selection

→ Backend exception thrown; input area broken

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.170 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

• Gateway client OS: Ubuntu 24.04.4 LTS (local laptop)
• Remote host OS: Ubuntu 22.04.5 LTS, Linux 5.15.0-179-generic
• Plugin version: com.anthropic.code.plugin 0.1.14-beta
• PyCharm: 2026.1.2 (261.24374.152)
• Gateway: 2026.1.3 (261.25134.98)
• Resizing window, undocking, changing IDE theme: no effect
• Workaround: claude in integrated terminal works correctly

<img width="3676" height="693" alt="Image" src="https://github.com/user-attachments/assets/c5c10a66-12e7-4171-ac79-1e68ff93b1bb" />