How to save the created diagram in IDEA?

Question

IntelliJ IDEA

Here I click on the desired folder with the right mouse, select in the context menu: Diagrams → Show Diagram... → Java Class Diagrams and a picture appears, where all classes are presented. I drag them from place to place, arranging them as needed, saving the file... And here is the problem: in the saved file, the classes are not shown at all in the places where they were at the time of saving, but as they were at the moment the diagram window was first opened.
How to fix it?