Cannot drag-and-drop with right mouse button from the toolbar breadcrumbs themselves
This was tested Thunar 4.16.8 via Mint Xfce 20.3, Thunar 4.16.10 vis Mint Xfce 21.0, and Thunar 4.16.11 via Manjaro Xfce 21.3.7 (unfortunately I have no idea on an easy way to test Thunar 4.17.x).
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You know how, if you right-click on a breadcrumbs, it shows a context menu that is basically identical to if you had right-clicked on the folder itself?
Well it turns out that, unlike right-clicking on a folder, one cannot do a right-click drag-and-drop from the toolbar breadcrumbs themselves (which is something I tried to to recently when I wanted to make a shortcut from the folder I was already viewing).
By contrast, one can still do a left-click drag-and-drop while holding shift, ctrl, or shift+ctrl to perform the usual "copy, link, etc" actions that you'd normally have access to when doing a right-click drag-and-drop.