This can be used to hide icons in the map on hidden map parts, so if a map part is not enabled, the icons inside that map part are disabled too and once the map part is enabled, the icons will be shown in the map as well.
For this, go to the Map Object Information inspector and enable the option Belong To Map Part.
Then, select the Map Part Owner, which means the map part that contains that icon. Use the list of map parts to select where the icon belongs. This list is shown according to the Floor Number configured in the inspector.
The list of floors is configured automatically from the map floors configured in the Map Creator inspector.
Like this, if you select the floor-000, it will appear the map parts list of that floor. In the left picture, the map part list shown belongs to the ground floor. In the right picture, the map part list belongs to the first floor.
In this example, the Map Object Information is used for a save station in the main hall room, which is disabled until the player enters the room. Also, 3 doors are configured with the same unlock values.