GUIDE
Shiny debug mode
A dedicated mode for tracing reactive dependencies, spotting invalidation loops, and fixing UI/server mismatches.
When to use it
- Outputs that stop updating after a filter change
- Observers firing twice on startup
- Module namespace or ID collisions
- Performance: reactives recomputing on every keystroke
Workflow
- Paste ui and server code into the context panel
- Select Shiny debug mode in the playground
- Describe the symptom — what you expected vs what happened