Bug 174272 FileStoreEditorInput needs to be restorable
3.3 M5 The FileStoreEditorInput needs to restorable on startup. Therefore it needs to return an IPersistableElement and there needs to be an element factory.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/IDE.java
*      boolean)
	 */
	public static IEditorPart openEditor(IWorkbenchPage page, IFile input,
			String editorId, boolean activate) throws PartInitException {
		
		if (page == null) {
			throw new IllegalArgumentException();
		}
		
		return page.openEditor(new FileEditorInput(input), editorId, activate);
	}
	/**
	 * Returns an editor descriptor appropriate for opening the given file
	 * resource.
	 * <p>
	 * The editor descriptor is determined using a multi-step process. This
	 * method will attempt to resolve the editor based on content-type bindings
	 * as well as traditional name/extension bindings.
	 * </p>
	 * <ol>
	 * <li>The file is consulted for a persistent property named
	 * <code>IDE.EDITOR_KEY</code> containing the preferred editor id to be
	 * used.</li>
	 * <li>The workbench editor registry is consulted to determine if an editor
	 * extension has been registered for the file type. If so, an instance of
	 * the editor extension is opened on the file. See
	 * <code>IEditorRegistry.getDefaultEditor(String)</code>.</li>
	 * <li>The operating system is consulted to determine if an in-place
	 * component editor is available (e.g. OLE editor on Win32 platforms).</li>
	 * <li>The operating system is consulted to determine if an external editor