Everything was handling palette change already but for the visual distinction between active and non-active view (in case of split view), a custom palette was set which was then never updated. This could be seen by the label text color changing but not the view background.

BUG:

Changed from Breeze and Breeze Dark and vice-versa and Dolphin's file view picked it up immediately, both in split and single view mode. Also verified that the active and inactive view are still visually distinct

(I bet there is a bug report about this but I cant find one right now)