1. Use Safari browser
2. Create a page, insert a diagram with one shape only, and save the page
3. Edit the page, edit the diagram, and add a second shape
4. Click 'Save' and note the title of the diagram in Gliffy now shows v2.
5. Exit Gliffy. Note that the editor is showing v2 of the diagram, with both shapes
6. Click on the diagram, and click 'Edit' on the property panel. Note that the diagram you are editing is now v1, with only one shape.

Confluence v5.6-OD-34 (current production)
Gliffy add-on v6.2.2