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
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.Preferences;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.preference.PreferencePage;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchPreferencePage;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
import org.eclipse.ui.internal.ide.IIDEHelpContextIds;
import org.eclipse.ui.internal.ide.ResourceDragAndDropEditor;
/**
 * Preference page for linked resources. 
 * This preference page allows enabling and disabling the workbench linked 
 * resource support.
 * It also shows all path variables currently defined in the workspace's path 
 * variable manager. The user may add, edit and remove path variables. 
 *  
 * @see org.eclipse.ui.internal.ide.dialogs.PathVariableDialog
 */
public class LinkedResourcesPreferencePage extends PreferencePage implements