Ask the user what to do with the data.
Copy the data.
Means nothing, and should not be used.
Add a link to the data. Note that this is only useful if source and destination agree on what it means.
Move the data, i.e. first copy it, then delete it from the source using the DELETE target of the X selection protocol.
Special action which tells the source that the destination will do something that the source doesn’t understand.
Used in Gdk.DragContext to indicate what the destination should do with the dropped data.