Honestly, don't know if this is expected or not but..
Is it really necessary for the layout pages to open when we open the content pages?
I believe it is because code gets added to the layout page head tag and it needs to be saved. That's from my limited Node experience anyways.
When the code being added to the layout page, it is automatically saved. Hence, this is a very valid question
On a personal note, the opening of the layout page does not bother me. That way I do not have to open it manually to check the added code for correctness.
Experienced the same. I wish it didn't open unless we manually open it.
The layout page will only open if some changes are needed in the head tags when you open a content page. It does not always open.