ok it works well,

but when i can't do it for image, if the nodes have and image, the text will follow according to the span but the image don't, any suggestions???

Oh, sorry for that, it seems that directly injecting HTML may have adverse effect on some functionality of the tree.

The good news is that I discover the official alternative :) Which is much easier and cleaner to implement, and works fine with NodeClick.

<ignav:node Text="Child Node">
   <Margin Left="-15px" />
</ignav:Node>

Hope this helps.