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
* @param pageName
	 *            the name of the page
	 * @param selection
	 *            the current resource selection
	 */
	public WizardNewFileCreationPage(String pageName,
			IStructuredSelection selection) {
		super(pageName);
		setPageComplete(false);
		this.currentSelection = selection;
	}
	/**
	 * Creates the widget for advanced options.
	 * 
	 * @param parent
	 *            the parent composite
	 */
	protected void createAdvancedControls(Composite parent) {
		Preferences preferences = ResourcesPlugin.getPlugin()
				.getPluginPreferences();
		if (preferences.getBoolean(ResourcesPlugin.PREF_DISABLE_LINKING) == false) {
			linkedResourceParent = new Composite(parent, SWT.NONE);
			linkedResourceParent.setFont(parent.getFont());
			linkedResourceParent.setLayoutData(new GridData(
					GridData.FILL_HORIZONTAL));
			GridLayout layout = new GridLayout();
			layout.marginHeight = 0;
			layout.marginWidth = 0;
			linkedResourceParent.setLayout(layout);
			advancedButton = new Button(linkedResourceParent, SWT.PUSH);