There's currently no way to identify if an item is part of a matrix or not. This would be incredibly useful to know.
Potentially the column could show an icon or something simple to just indicate that it has a parent item.
When an item is in a matrix the description is not editable from the quick edit menu.
When an item is a not in a matrix, you can edit the description right there.
Nice sleuthing SethM, that helps for the Quick Edit Items page. Would still love something implemented for the Item Search page though too! :)
@commuter You can filter by Item Type in the Item Search page. This will show you what items are Matrix and which aren't. Also, when you open an item it will say below the image space whether or not it's part of a Matrix. Hope that helps.