Context is not clear but shared between tabs

**Describe the bug**

People create new tab to get fresh ideas. But currently, Copilot shares the context and leads errors.

**Versions**
- Copilot for Xcode: 0.37.127
- Xcode: 16.4 (16F6)
- macOS: 15.6 Beta(24G5054d)

**Steps to reproduce**
1. Ask copilot to change code for some times, for example, 4 times.
2. Use GitHub to restore to the original state.
3. Open a new tab, ask the first question.

Expected:
Copilot only dealt with the specific question.

What happened:
Copilot revised the code with the four questions. Even if you change the model, for example, from Sonnet 4 to Gemini 2.5 Pro, the result was the same.

**Screenshots**

**Logs**

**Additional context**