How to delete a list
To delete a custom symbol list from the watchlist, open the dropdown box at the top of the section and click on “Open list…” (or use the Shift+W hotkey). In the dialog that appears, hover over the list title, then click on the remove button.
A flagged list will be automatically deleted once all its content is cleared. This means that the list will be erased when all the symbols have been removed. To remove a symbol, you need to either un-flag it or click on the remove button.