Contributions from the same paper should be grouped / groupable under the same title
User story
As a comparison user I want to group 2 contributions of the same paper under one merged cell So that I don't see 2x the same title
Contributions from the same paper should be grouped / groupable under the same title like two merged columns. The user might still wnat to change this, e.g. P1_c1, P2_c1, P1_c2, P2_c2, so this should just happen for neighboring contributions of the same paper. This is a bit more complicated since the label might not be in the view for 20 contributions from the same paper, and making it sticky would be complicated.