[Bug] Copilot Plugin: Sluggish Response after a few requests

Environment

• OS: Windows 11 26200.9445 (25H2)
• Eclipse Version: 2026-06 (4.40.0)
• Plugin Version: 0.21.0.202608060743

Describe the bug
Text responses from Copilot slow down to about 2 to 3 words per second in the copilot window.
If I start a new session, it will be faster, but only for about 4-5 requests.

To Reproduce
Steps to reproduce the behavior:

1. Use Get coding help using Copilot.
2. Observe that the Copilot display gets more sluggish as responses increase.

** Message from Copilot itself:
You're describing a client-side UI rendering performance issue with the Eclipse Copilot plugin itself. This is beyond my control as the backend AI service—it's a plugin architecture or implementation problem.

What's likely happening:

1. Plugin buffer accumulation - The Eclipse plugin may be accumulating the entire response in memory and re-rendering it incrementally, which gets slower as the buffer grows.
2. DOM/UI update thrashing - The plugin might be doing expensive UI updates for each token streamed, and these updates compound over time.
3. Memory pressure - The plugin's local state may be growing, causing garbage collection pauses that slow token rendering.
4. Context size in plugin state - Similar to backend context issues, the plugin may be storing session context and slowing down as it grows.

This is a plugin bug, not something I can fix. You should:

•  Report this to Microsoft/GitHub Copilot team with details:
•  Plugin version
•  Eclipse version
•  Exact degradation pattern (fast initially, slows after 4-5 requests)
•  2-3 words/second rendering speed
•  Workarounds in the meantime:
•  Start fresh conversations every 3-4 requests
•  Use the VS Code plugin instead (if you have access) to see if it exhibits the same issue
•  Close and reopen the Eclipse plugin panel periodically

This is a known type of issue with streaming plugins—the Eclipse Copilot implementation may need optimization in how it handles incremental token rendering.

Reproduce the slowdown in the Eclipse Copilot plugin using the listed Windows, Eclipse, and plugin versions, making several requests in one session. Trace the response display path to determine why rendering degrades after four or five requests; done means responses remain responsive during continued requests without needing a new session.