eclipse-theia/theia

Active Editor not updating after restart

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#6,421 opened on Oct 21, 2019

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bughelp wantedplug-in systemvscode

Description

Description

After restart, selecting existing open editors does not update theia.window.activeTextEditor

Reproduction Steps

Create the HelloWorld example plugin

yo @theia/plugin

Update the code to show the language of the active editor as shown

testCode

Run the plugin in hosted mode and issue the 'Hello World' command. Initially the active editor is undefined as expected. Open a file HelloWorld command now shows the correct active editor.

Restart/Refresh the browser.

Select an existing editor and issue HelloWorld command The active editor is always undefined. Open a new file The command now reports the NEW active editor Select an old editor with different extension Clear the notification and issue the commend The wrong editor is now reported showing the newly opened editor rather than the older one.

OS Windows/Linux, Theia version: 10

testRun

Contributor guide

Tech stack
typescript
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScript basicsTheia plugin API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The issue involves the active editor not updating after restart. Focus on the plugin system and editor lifecycle in the Theia source code. Look at packages/plugin/src/theia plugin.ts for how editors are tracked and the api implementation. Also check the editor manager in packages/editor/src/browser/editor manager.ts for state restoration. The issue is likely in the plugin host process failing to re register active editor listeners after a restart. Reviewing the 'onDidChangeActiveTextEditor' event implementation and window state restoration would be key.