You are right
Shop association is added in page properties - CMS section.
Originally, PrestaShop Backend doesn't have filter option for whole page in CMS section.
So you can work with current selected shop.
You are right - I added this suggestion in our future to-do list.
Comments are welcome.
Just a reminder that this is not fixed yet and in multishop setups where each shop has many different cms pages there is no way to handle the pages correctly with the Store Manager. Its been 8 months already, I hope this can be added soon.
Dec 17, 2015
Thanks for reminder.
This task in our development line.
So I'm waiting for this stage.