Bug 134740 [Wizards] PDE product wizard is not obvious to use.
see attached image. The wizard for creating a new product opens with a file name initialized to ".product" which is selected. Generally this would imply that this is a good default but if you start typing you will replace the text with something else that is also a good name. If you require an extension for a file you should add it yourself like the "Export Archive" wizard.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/dialogs/WizardNewFileCreationPage.java
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.ide.undo.CreateFileOperation;
import org.eclipse.ui.ide.undo.WorkspaceUndoUtil;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;
import org.eclipse.ui.internal.ide.IIDEHelpContextIds;
import org.eclipse.ui.internal.ide.dialogs.CreateLinkedResourceGroup;
import org.eclipse.ui.internal.ide.misc.ResourceAndContainerGroup;
/**
 * Standard main page for a wizard that creates a file resource.
 * <p>
 * This page may be used by clients as-is; it may be also be subclassed to suit.
 * </p>
 * <p>
 * Subclasses may override
 * <ul>
 * <li><code>getInitialContents</code></li>
 * <li><code>getNewFileLabel</code></li>
 * </ul>
 * </p>
 * <p>
 * Subclasses may extend
 * <ul>
 * <li><code>handleEvent</code></li>
 * </ul>
 * </p>
 */
public class WizardNewFileCreationPage extends WizardPage implements Listener {