MT5 · Compilation errors
MT5 399 · Interface objects cannot be created directly, only use inheritance | YI GOLD
Official meaning
Interface objects cannot be created directly, only use inheritance
Possible causes · YI GOLD suggestions
Object names, types, properties, coordinates or chart subwindows do not match.
Troubleshooting · YI GOLD suggestions
Verify chart ID, object existence and property types. Check creation/update results and avoid name collisions.