Why the NotchStar shelf does not open for text or images
The shelf only reacts to files. When you drag a selection of text, or an image straight out of a web page, there is no file on the drag, so the notch stays closed and the shelf zone will not accept a drop. This is a stated limit of the Shelf, not a setting you can change.
Why
NotchStar checks what you are dragging. It opens the Shelf only when the drag carries a file reference, the same kind of item Finder gives you. A web page image is usually a link or raw image data, not a file on your disk.
What to do instead
- Image on a web page. Save it first (right click, then save), then drag the saved file toward the notch.
- Text. Copy it. The Clipboard tab keeps your recent copies, and you can put the text back on the clipboard from there.
- Text to keep for later. Use Quick Notes.
- A screenshot. The Screenshot Tray holds fresh screenshots and has its own drag out.
Check you are dragging a file
If you can see the file in Finder, it is a file. A file dragged out of a Finder window or the Desktop works every time as input to the shelf.
The rest of the Shelf is covered on the File Shelf page. To learn the gesture, read how to open the shelf by dragging.