Bug 65444 [R21PRES] Close button shown when views not closeable
RC1 build - run the browser example using the R2.1 presentation - the views have close buttons in the titlebar, but should not because the perspective has fixed="true" (meaning that all initial views are non-moveable and non-closeable)
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21BasicStackPresentation.java
/**
	 * Returns the index of the tab for the given part, or returns tabFolder.getItemCount()
	 * if there is no such tab.
	 * 
	 * @param part part being searched for
	 * @return the index of the tab for the given part, or the number of tabs
	 * if there is no such tab
	 */
	private final int indexOf(IPresentablePart part) {
		if (part == null) {
			return paneFolder.getItemCount();
		}
	
		CTabItem[] items = paneFolder.getItems();
		
		for (int idx = 0; idx < items.length; idx++) {
			IPresentablePart tabPart = getPartForTab(items[idx]);
			
			if (part == tabPart) {
				return idx;
			}
		}
		
		return items.length;
	}
	
	/**
	 * Returns the tab for the given part, or null if there is no such tab
	 *