Drag-and-drop does not work for Firefox 12

We are trialing confluence 4.2.2, downloaded.

In Firefox 12:

When editing a page, I can drag and drop an image, and it attaches to the page, but the image doesn't show. If I click "preview" I can see it, but if I click edit again I can't.

If I upload the image via "insert image", then drag and drop it will show in the edit window.

I can't move any existing image around on the page by dragging.

Everything works fine in Chrome.

The existence of this bug has been confirmed by a 3rd party