Labels are not visible

Steps to reproduce

1. Edit or Add a page or a blogpost
2. Click "Labels" and add a label
3. The number of the Label button is set to 1 - correct
4. Close the popup window
5. Click on the button "Labels" again and no labels is visible
6. Save the page and the labels are visible

This only happened when the page is in edit mode. If you try to add labels directly from the page, it works fine.