Is there a way to tune/update file resolving?

[ard]

Ok, I’ve just start it for the first time and tried to merge sth with conflicts.
When I click “resolve” it brings 3-way merge tool that looks rather nice at first sight allowing me to decide what I want in the result. Then I click “save” and see the result on “main merge screen” (I don’t know how to call it).
Supposing now I see that sth isn’t correct yet. Then I go to to “resolve” screen again in order to tune the result.
But surprisingly instead seeing my previous work, often not trivial and worked out in sweat and pain I see everything undone so I can plunge into it again. Have I missed something or I’ve just discovered a lack of FUNDAMENTAL feature?