For a long time, Kdenlive displays only a small indication ">" when a transition in the timeline has a target track different from the next lower track. When doing more complex compositing using multiple transitions in Kdenlive, it's impossible to tell from the timeline itself which transitions composes onto which other track. Users need to click on a transition first, then inspect the "with" drop-down list in order to find out the target track.
Some other multi-track video editors, such as flowblade, provide clear visible means in the timeline of the transition composition setup. For instance, flowblade shows a downpointing arrow near the beginning of a transition in the timeline. This arrow extends down to the particular lower track the transition uses as the target track.
It could be a usefull UI improvement, as well as better usability, if Kdenlive could also indicate the target track of a transition in the timeline.