I need collapse/expand groups that do not stretch when used. How?

[artut...@gmail.com]

Title, I am using Draw.io to make IDEF0 and arrow order (side of the diagram they enter and exit from etc) is important, so I need the whole diagram to stay like I set it up and not move when I collapse/expand groups.
Collapse/expand is vital and is the more important function. But I need that when I click the +/- button it just obscures the content and groups the arrows (everything like it does now) except resize itself.
Is there a way to not make it shrink?
Thanks in advance.

[Gaudenz Alder]

The collapsed size is persisted, so if you resize it to match the uncollapsed size that should persist.

[artut...@gmail.com]

Works well enough, except for a few things that are off.
I'll show you a few screens to explain what I mean.

https://i.imgur.com/hchdY27.png?1
This is the open group with all things set up and in order like I want.

https://i.imgur.com/RArBGC5.png?1
This is when the group is collapsed (with the same size as the expanded group, like you suggested).
As you can see, the blue arrows on the bottom of the group cut perfectly and arrange neatly on the border when it's closed, like it should be.
The red arrows that come out from the right and go off screen also stay arranged.
The red arrows from the top and the very obvious green arrow in the center of the box however (that comes out from the right border of the collapsed box, loops around and then goes back again) somehow are acting up.
What could be causing that? The arrows are set up the same, both on top and on the bottom, so they shouldn't act differently from one another.

Thanks for the very quick answer and help.