Thanks for the feedback! We are working on enabling this feature.
An error occurred while saving the commentArash Motamedi commented
This is much needed. Consider this scenario: 1. Publish new site to staging. 2. Swap to prod. 3. Need minor tweak in an HTML file, update and partially publish (just the modified file) to staging. Now, my staging area has an old site with a new HTML file... Oops! Things got mixed up and can't proceed to swapping without a full deployment to staging.
So, there's a need that after a swap (and successfully verifying that the new site is well), there should be a way to copy the new production bits back into the staging slot, so both staging and production have the latest bits.