Items within the Menu Item Manager have various states;
Published so they are visible to those who have the permissions to see them,
Hidden from everyone apart from the editors who have the right to see them or,
Archived so whilst they do not appear in the site tree on the front end of the web site they are accessible to the TurnKey internal search engine.

Over time your Item Manager could become quite large and take a little time to reload when you make changes. TurnKey offers an item filter to make life easier. Simply click on the filter and choose what you want to see on the Menu Item Manager. Just another helpful tool to make you day a little easier!