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
case IPresentablePart.PROP_TOOLBAR:
		 case IPresentablePart.PROP_PANE_MENU:
		 case IPresentablePart.PROP_TITLE:
		 	setControlSize();
		 	break;
		}
	}
	protected final IPresentablePart getPartForTab(CTabItem item) {
		IPresentablePart part = (IPresentablePart)item.getData(TAB_DATA);
		
		return part;
	}
	
	/**
	 * Returns the underlying tab folder for this presentation.
	 * 
	 * @return
	 */
	protected R21PaneFolder getPaneFolder() {
		return paneFolder;
	}
	
	/**
	 * Returns true iff the underlying tab folder has been disposed.
	 * 
	 * @return
	 */
	public boolean isDisposed() {
		return paneFolder == null || paneFolder.isDisposed();
	}