Bug 12720 Can't DND into non-source folder in Packages view
Build 20020321 In the Packages view, I can drag a file from the file system onto a project, a package or a source folder. However I cannot drag it onto a non-source folder. I can, however, drag the file onto the project, and then drag it into the non- source folder from within the packages view. The packages view should allow me to drag a file into any folder, just like in the Navigator view.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/FileTransferDropAdapter.java
} else {
			event.data= null;
			return;
		}
	}
	
	private List checkFiles(Shell shell, String[] files, IPath target) {
		List result= new ArrayList(10);
		int lengthCompare= target.segmentCount() + 1;
		for (int i= 0; i < files.length; i++) {
			String file= files[i];
			IPath path= new Path(file);
			String error= null;
			if (path.equals(target)) {
				error= PackagesMessages.getFormattedString("DropAdapter.errorSame", target.lastSegment()); 
			} else if (path.isPrefixOf(target)) {
				error= PackagesMessages.getFormattedString("DropAdapter.errorSubfolder", path.lastSegment()); 
			}
			if (error != null) {
				MessageDialog.openError(shell, PackagesMessages.getString("DropAdapter.errorTitle"), error); 
				return new ArrayList(0);
			}
			
			if (target.isPrefixOf(path) && lengthCompare == path.segmentCount())
				continue;
			result.add(new File(file));
		}
		return result;
	}	
}