Q:

Dojo tree not loading when adding theme

I followed this tutorial to connect a digit.tree to a store.JsonRest and everything works well.
Before adding a dojo theme The tree is display with pure html, actions work perfectly, I can display my tree branch by branch.
When I add a theme (claro in my case) the tree is loaded in memory (I use the dojo plugin for firebug to verify) but nothing is displayed.
There isn't any error in the console.
So if anyone have an idea. Thank you. 

A:

So, just to check, by "adding a theme", you mean linking in the appropriate Claro CSS file and marking the body with class="claro", and you're then finding that the previously-visible tree disappears?  (If you haven't marked the body as such, that may well be be your problem.)
If that's the case, use Firebug to check the sizes of the rendered elements in your page DOM (I presume they're still there).  If they've shrunk down to 0px x 0px or equivalent, try using Firebug to manually change the size of, say, the top-level element and see what effect that has.
You may need to override the sizes of some of the nodes, or the top-level tree itself, or ensure the html+body are bigger than 0px (e.g. 100%).

