Bug 63420 [R21PRES] Flash on tab switch
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21BasicStackPresentation.java
}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.internal.skins.StackPresentation#addPart(org.eclipse.ui.internal.skins.IPresentablePart,
	 *      org.eclipse.ui.internal.skins.IPresentablePart)
	 */
	public void addPart(IPresentablePart newPart, Object cookie) {
		int idx;
		if (cookie instanceof Integer) {
			idx = ((Integer) cookie).intValue();
		} else {
			
			idx = paneFolder.getItemCount();
		}
		addPart(newPart, idx);
	}
	/**
	 * Adds the given presentable part to this presentation at the given index.
	 * Does nothing if a tab already exists for the given part.
	 * 
	 * @param newPart
	 * @param index
	 */
	public void addPart(IPresentablePart newPart, int index) {
		
		if (getTab(newPart) != null) {
			return;