Bug 220767 [Dialogs] PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL
3.3.x and 3.4 M5. The SWT.TOOL flag should be used to create hover style shells, hence the PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/PopupDialog.java
* (value is 0).
	 */
	public final static int POPUP_MARGINHEIGHT = 0;
	/**
	 * Vertical spacing (in pixels) between cells in the layouts inside popup
	 * dialogs (value is 1).
	 */
	public final static int POPUP_VERTICALSPACING = 1;
	/**
	 * Vertical spacing (in pixels) between cells in the layouts inside popup
	 * dialogs (value is 1).
	 */
	public final static int POPUP_HORIZONTALSPACING = 1;
	/**
	 * Image registry key for menu image.
	 * 
	 * @since 3.3
	 */
	public static final String POPUP_IMG_MENU = "popup_menu_image"; 
	/**
	 * Image registry key for disabled menu image.
	 * 
	 * @since 3.3
	 */
	public static final String POPUP_IMG_MENU_DISABLED = "popup_menu_image_diabled"; 
	/**
	 * 
	 */
	private static final GridLayoutFactory POPUP_LAYOUT_FACTORY = GridLayoutFactory
			.fillDefaults().margins(POPUP_MARGINWIDTH, POPUP_MARGINHEIGHT)