Bug 310494 [LinkedResources] Preference "Link and create virtual folders" does not work
I20100425-2000 The 2 options on the Linked Resourced with name "Link and create virtual folders" don't work. When they are selected, dropping items does nothing. In CopyFilesAndFoldersOperation#copyOrLinkFiles(..), the test "hasFlag(dropOperation, ImportTypeDialog.IMPORT_VIRTUAL_FOLDERS_AND_LINKS)" always fails because dropOperation is always COPY.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/CopyFilesAndFoldersOperation.java
* Recursively collects existing files in the specified destination path.
	 * 
	 * @param destinationPath
	 *            destination path to check for existing files
	 * @param copyResources
	 *            resources that may exist in the destination
	 * @param existing
	 *            holds the collected existing files
	 */
	private void collectExistingReadonlyFiles(IPath destinationPath,
			IResource[] copyResources, ArrayList existing) {
		IWorkspaceRoot workspaceRoot = ResourcesPlugin.getWorkspace().getRoot();
		for (int i = 0; i < copyResources.length; i++) {
			IResource source = copyResources[i];
			IPath newDestinationPath = destinationPath.append(source.getName());
			IResource newDestination = workspaceRoot
					.findMember(newDestinationPath);
			IFolder folder;
			if (newDestination == null) {
				continue;
			}
			folder = getFolder(newDestination);
			if (folder != null) {
				IFolder sourceFolder = getFolder(source);
				if (sourceFolder != null) {
					try {
						collectExistingReadonlyFiles(newDestinationPath,
								sourceFolder.members(), existing);
					} catch (CoreException exception) {
						recordError(exception);