Polymer Designer always deletes everything

[mhoppi]

When i put element in polymer designer into the canvas and switch between code and designer, i can see the element in code modus, but when i switch back to designer, element is gone (also the code). I cant save the elements and on previw only shows an empty page.

I can neither place a field inside a card...

[robdodson]

Dupe: Polymer/designer#61