Bug 302441 [LinkedResources][CommonNavigator] When to show "Files and Folders Operation" dialog on drop
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/LinkedResourcesPreferencePage.java
IWorkbenchPreferencePage {
    private Label topLabel;
    private PathVariablesGroup pathVariablesGroup;
	private ResourceDragAndDropEditor dragAndDropHandlingEditor;
    /**
     * Constructs a preference page of path variables.
     * Omits "Restore Defaults"/"Apply Changes" buttons.
     */
    public LinkedResourcesPreferencePage() {
        pathVariablesGroup = new PathVariablesGroup(true, IResource.FILE
                | IResource.FOLDER);
        this.noDefaultAndApplyButton();
    }
    /**
     * Resets this page's internal state and creates its UI contents.
     * 
     * @see PreferencePage#createContents(org.eclipse.swt.widgets.Composite)
     */
    protected Control createContents(Composite parent) {
        Font font = parent.getFont();
        PlatformUI.getWorkbench().getHelpSystem().setHelp(parent,
                IIDEHelpContextIds.LINKED_RESOURCE_PREFERENCE_PAGE);
        
        Composite pageComponent = new Composite(parent, SWT.NULL);
        GridLayout layout = new GridLayout();
        layout.marginWidth = 0;
        layout.marginHeight = 0;
        pageComponent.setLayout(layout);
        GridData data = new GridData();
        data.verticalAlignment = GridData.FILL;