Drag-and-drop is a common way of moving files around in Windows. In Opus, drag-and-drop is controlled by the File Types system.
The default behavior is the same as in Explorer:
Internally, these actions are defined by the items on the Events tab for the All files and folders file type. Whereas in Explorer these actions are fixed, in Opus they are configurable.
This screenshot shows the File Type editor for the All files and folders file type. The events are all defined as some variant of the internal Copy command.
Although not shown here, the Drop Menu tab also defines the contents of the menu shown when dragging with the right mouse button. This can also be configured.
Editing these functions modifies the drag-and-drop behaviour in Opus. For example, if you wanted drag-and-drop to always copy (rather than moving on the same drive), you could edit the command definition to Copy RENAMEWHENSAME (the same as the Drag-and-drop+Ctrl event).
The All files and folders file type is a special file type that by definition matches everything - both files and folders. You can use the File Types system to define overriding events for specific file types. For example, you could configure drag-and-drop of a Zip file to extract the contents of the archive when dropped with the Shift key held down.
See the documentation on the File Types system for more information.