Bug 94674 [Preferences] Preferences dialog separator under Title for pages does not stretch all the way across
The separator under the Header title for a preference page should stretch from the border of the sash to the far right with no margins in between.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
* return code to <code>CANCEL</code> and closes the window using
	 * <code>close</code>. Subclasses may extend or reimplement.
	 * </p>
	 */
	protected void handleShellCloseEvent() {
		
		cancelPressed();
	}
	/**
	 * Notifies of the pressing of the Help button.
	 * <p>
	 * The default implementation of this framework method calls
	 * <code>performHelp</code> on the currently active page.
	 * </p>
	 */
	protected void helpPressed() {
		if (currentPage != null) {
			currentPage.performHelp();
		}
	}
	/**
	 * Returns whether the current page is valid.
	 * 
	 * @return <code>false</code> if the current page is not valid, or or
	 *         <code>true</code> if the current page is valid or there is no
	 *         current page
	 */
	protected boolean isCurrentPageValid() {
		if (currentPage == null)
			return true;