1. Create an expression menu
  2. Create sub menu with toggle for parameter which doesn't exist
  3. create menu item in main expression menu and link submenu
  4. change menu item type from submenu to toggle
Current behaviour:
VRChat SDK shows "VRCExpressionMenu uses a parameter that is not defined. Parameter: <your parameter name>" and blocks upload
Expected behaviour:
No warning/error in SDK window
SDK: 3.7.1