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 activate, boolean determineContentType)
			throws PartInitException {
		
		if (page == null) {
			throw new IllegalArgumentException();
		}
		
		IEditorDescriptor editorDesc = getEditorDescriptor(input,
				determineContentType);
		return page.openEditor(new FileEditorInput(input), editorDesc.getId(),
				activate);
	}
	/**
	 * Opens an editor on the given file resource. This method will attempt to
	 * resolve the editor based on content-type bindings as well as traditional
	 * name/extension bindings.
	 * <p>
	 * If the page already has an editor open on the target object then that
	 * editor is brought to front; otherwise, a new editor is opened.
	 * <p>
	 * 
	 * @param page
	 *            the page in which the editor will be opened
	 * @param input
	 *            the editor input
	 * @return an open editor or <code>null</code> if an external editor was
	 *         opened
	 * @exception PartInitException
	 *                if the editor could not be initialized
	 * @see org.eclipse.ui.IWorkbenchPage#openEditor(IEditorInput, String)