Sending request role.update for any role, with parameters "ui.default_access": 0 - disable all UI elements. 

Steps to reproduce: 

1) Create request "role.update"

2) Add params as - 
"roleid": "5",
"rules":

3) Send request.
Result:
All UI elements for role are disabled. 

Expected:
Error message, that at leas 1 UI element should be enabled.