cannot bind to property "native" on Dropupload component (org.zkoss.zkmax.zul.Dropupload)

<dropupload id="upload" maxsize="5120" detection="none" onUpload="@command('onUpload', event=event)" native="@bind(vm.nativeUpload)">

this error message is thrown -->
The identifier [native] is not a valid Java identifier as required by section 1.19 of the EL specification (Identifier ::= Java language identifier). This check can be disabled by setting the system property org.zkoss.zel.impl.parser.SKIP_IDENTIFIER_CHECK to true.

same might happen for Fileupload (but here the property is already deprecated)