Great find! Thanks for reporting, Nico. I’ll share with the team and find out why plan mode isn’t working 
As a workaround, you can create a custom instruction that achieves similar behavior:
- Click the + button in the prompt bar
- Select New Instruction
- Title:
Plan Mode - Rule:
Before implementing any code changes, create a detailed plan outlining the approach, steps, and potential challenges. Ask for approval before proceeding with implementation.
Hope that helps!