When you are editing a diagram and you wish to open an other one.
You click on the small + above the drawing panel.
You have the whole of the diagram present in the space.
When you have 4 diagrams, it is fair but when you have 150 diagrams it becomes a nightmare to find the diagram.
It will be nive to reproduce the page tree of the space in the left part and when you click on a page name you have the diagram of the selected page and all the diagrams of its descendance.