Orion supports the common macOS option-drag interaction (drag-and-drop an item while holding down the option ⌥ key) for duplicating objects in the Bookmarks window. It does not, however, display the proper "Plus" pointer icon when the option key is down.
Note how, in the video, the bookmark is duplicated, but the pointer only displays the plain arrow:
While the user holds down the option key, the pointer should display the "Plus" icon. That allows the user to have a clear expectation of what will happen when they lot go of the mouse button.
Here's how that works in Safari:
(N.B. In the Orion video above, I had to have the screen recording app display the key press. In the Safari video, that was not necessary, because of the "Plus" pointer. I rest my case! 😉)
Orion 1.0.8; macOS 26.5.1
Tahoe (26)