When Show Icons is selected in the Memory Locations pop-up menu, the Memory Locations window provides an icon-based “View Filter” that lets you show or hide Memory Locations based on the properties they contain.
If an icon is disabled (grayed out), all Memory Locations associated with that property are hidden. However, if a Memory Location contains other properties for an icon that is enabled, it is still displayed.
In addition, the View Filter provides a useful reference for which properties are stored in each Memory Location (indicated by a row of icons for each Memory Location).