Cannot apply changes made to RectTransform of world space canvas

When I set the canvas to screen space, Canvas automatically goes full screen and its resolution and scale will be set automatically. When I convert the canvas to world space, values remain but I can't apply them to prefab.
Any ideas?

 

Some of the root Transform properties are default overrides. See the documentation, header "Alignment is specific to Prefab instance".

You can edit those properties in the Prefab by going into Prefab Mode and editing them there.

 

Well, that's clever that you don't mark transform changes as overrides.

Let me explain my use case. I want to have some full-screen world space canvases. My solution to get perfect canvas was to set the canvas to screen-space and then once the RectTransform values get calculated, I change it to world space and hit apply.
Can I achieve the same thing in Prefab Mode?