[Isomorphic]

The default rendering you're seeing isn't due to Canvas children, it's the innerHTML of the widget. You can get rid of it with an override of getInnerHTML that returns empty content ( ).

[agalataud]

Perfect, it works. Thanks

[agalataud]

By the way could you please let me know when the first issue (calling addChild outside of the handler) will get fixed?

[Isomorphic]

The underlying issue with calling addChild() in the constructor should now be fixed in the nightly builds for 5.0d.