Classes that override parent class properties don't work nicely with QWebchannel

Build simple program. QDIalog cannot be exported from QWebchannel to javascript.

Javascript code broke at:

console.log(TypeError: Attempting to change the setter of an unconfigurable property.) at qrc:///qtwebchannel/qwebchannel.js(380)

And of course the further execution of the JavaScript program violated.

Source code sample program attached.