diff --git a/playground/matplus/dan-funk/simple-user-task-uischema.json b/playground/matplus/dan-funk/simple-user-task-uischema.json
index 6433563e..62e3d285 100644
--- a/playground/matplus/dan-funk/simple-user-task-uischema.json
+++ b/playground/matplus/dan-funk/simple-user-task-uischema.json
@@ -7,7 +7,7 @@
     "ui:enableMarkdownInDescription": true,
     "ui:description": "Make text **bold** or *italic*. Take a look at other options [here](https://markdown-to-jsx.quantizor.dev/)."
   },
-  "lastName": {
+  "last_name": {
     "ui:autocomplete": "given-name",
     "ui:enableMarkdownInDescription": true,
     "ui:description": "Make things **bold** or *italic*. Embed snippets of `code`. <small>And this is a small texts.</small> "