Re-enabling dragging from NSTableView to other applications

Q:  When I rebuild my application on Mac OS X version 10.2, my NSTableView loses the ability to drag-and-drop to other applications. How do I fix this?

A: When I rebuild my application on Mac OS X version 10.2, my NSTableView loses the ability to drag-and-drop to other applications. How do I fix this?

A bug in NSTableView in Mac OS X version 10.2 and later causes cross-application drags to not work without additional code from the application developer. Drag-and-drop within an application still works correctly. You can work around the bug by subclassing NSTableView and overriding -draggingSourceOperationMaskForLocal: to return the appropriate NSDragOperation (typically NSDragOperationCopy, depending upon what drag operation you want the drag-and-drop to perform). Only applications built on Mac OS X version 10.2.x are affected; applications built on 10.1.x are not affected.

This issue was resolved in Mac OS X version 10.4. For compatibility with that release and later, it is not necessary to subclass NSTableView in order for inter-application dragging that originates with the table view. It is, however, necessary to configure the table view by calling the setDraggingSourceOperationMask:forLocal: method. This is described in more detail in Using Drag and Drop in Tables at the end of the section "Beginning a Drag Operation".

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