There are two actions that can take place when an object is dropped: insert or load.
The insert action inserts the dropped object into the destination, adding it to the current data in the application or document. The object is inserted when a user schedules an appointment, prints a document, attaches a document, pastes text, or appends a mail message. Such an action is a move or copy operation depending on the destination and the user. The user might decide to copy a piece of selected text, as opposed to moving it. The drag icon should indicate whether the operation is a copy or move.
The load action operates the same as if the user had chosen Open from the File menu, selected a file, and clicked the Open button. The dropped object gets loaded into the application. The user can edit it and save changes back to the original file. Load only works with files at this time, not with buffers or text. The user should see the copy drag icon when dragging an object over a drop zone that supports the load action.
Load does work with buffers; however, buffers are loaded as read-only. See the section on "Attachment User Model"for more details.