Started Scrum Board: Layout

in the scrum board the presentation has changed. 
For about 2 weeks the outer columns ("backlog" & "erledigt") are wider than the middle Scrum columns. 
As a result, the text in the weighted middle columns is no longer easy to recognize. Why is that changed like this and how can this be reversed? In addition, some project members (our customers) in the ticket can no longer see to which Sprint the tickets belong. How can I (not an admin) change this?