Add infobox for overlapping items/videos in Timeline Viewer
Because it is still difficult to understand the concept of a Timeline, I still need to help people because they position videos on the Timeline in a way that they accidentally overlap. Users still don't understand why they are displayed next to each other and why they share the same annotations although the videos don't relate to each other (in case they were not explicitly introduced to the concept of the Timeline; but even then, they sometimes just forget about it).
I don't know how to solve this. It's really a critical thing in terms of UX/usability.
For now I would suggest to add a help-button if there are overlapping items (see screenshots below). The help button should only show up if there are overlapping items. The info box should display this info text:
"Why do I see two or more items side by side and not one below the other?
When items appear side by side on the Timeline, it means that they overlap in time on the Timeline or have been synchronized. To prevent unintended overlapping, select the "After last files" option when adding media files to the timeline or select the custom start time in a way that overlaps are avoided."