The sets in the element datasets panel can be duplicated

1. Pick a non-folder element that has child elements, for example a page with text lines.
2. Put any text line in a dataset.
3. Open the parent element.
4. In the children tree, click on the text line.
5. The dataset is shown 4 times.
   
6. Refresh the page.
7. The dataset is only shown once.
8. Cry.