Plan Mode dialog reappears after switching to another agent and back with /agent

What version of Codex CLI is running?

codex-cli 0.98.0

What subscription do you have?

Plus

Which model were you using?

_No response_

What platform is your computer?

Linux 6.6.87.1-microsoft-standard-WSL2 x86_64 x86_64

What terminal emulator and version are you using (if applicable)?

WSL

What issue are you seeing?

I found a bug related to Plan Mode and multi-agent workflows.

What steps can reproduce the bug?

Environment

• Feature: Plan Mode + multi-agent task creation
• Command used: /agent
• Context: Start from main conversation, create a multi-agent task, switch to another agent, then switch back

## Steps to Reproduce

1. Enter Plan Mode in the main conversation.
2. Create a multi-agent task.
3. Use /agent to switch to another agent conversation.
4. Use /agent again to switch back to the main conversation.

What is the expected behavior?

_No response_

Additional information

_No response_