Saving aircraft config

[Butch]

I've been trying to save an aircraft config, locating where to place the boarding ladder and a lot of times the save button is grayed out.
Why is that? If I press the slew "Y" key as mentioned in the manual, that doesn't always save what I want. In some cases, the bus will come
out with the pax and no ladder will show. I don't know why sometimes the SAVE will be active and sometime grayed out.

See pic

https://i.postimg.cc/zX1syrjx/Capture1.jpg

Edit: I find that if I copy the coordinates and enter them, the save button will not be grayed out and is functional, ego a save function is possible with the save button.

[virtuali]

When you are editing a door using the 3D editor, pressing Y to exit the 3D and going back to the dialog, will have all the modications saved automatically, that's why the "Apply" is greyed, it's as if it was just Applied ( by exiting the editor ) so, you can be sure the changed you made in the 3D editor HAS been saved.

Instead, when editing something in the numeric dialog, the Apply button will become active and waiting to be pressed to save the changes.