If I click "Save and continue" -- should it publish the post?
ETA
Yes it published it. And only afterwards the drop-down list with an option "Drafts for XiXiDu" appeared.
ETA #2
This is a bug, don't punish people with downvotes for publishing their unfinished drafts.
People don't expect their draft to be published when they click "Save and continue" if there is a "Submit" button.
This is a bug, how can you call it anything else?
If no one wants to take the time to fix "save and continue" so it does what it should, then perhaps someone could take the time to remove the "save and continue" button from discussion posts edit window. Then submit is actually listed as the only choice, which is rational since it is the only choice.