Part 5 of the series: "Extending bpmn-io Form-JS Beyond Its Limits" I built my first properties panel provider by copying the official example, changing the field type check, and adding my entries. It worked. Then I built the second provider, copied the same pattern, and my first provider stopped working correctly. Some entries disappeared. Some appeared in the wrong order. One entry showed up twice with different values. I had no idea why. The official documentation shows you the happy path — one provider, basic entries, everything works. It doesn't explain the contract that makes the system work, what breaks the contract, or why the system fails silently when you break it. After building 12 providers — for disabled state, readonly state, required validation, FEEL bindings, hide-if conditions, conditional rules, auto-fill logic, tab titles, grid configuration, dropdown configuration, image validation, and ticket auto-fill — I know the contract completely.…