Define a map drop point
This procedure defines points in the map where topics and other maps may be easily inserted.
The map must be locked.
You can specify a document within a map as a insertion point where other documents (topics and maps) may be added. This is particularly useful if you are adding topics to specific sub-trees of a large and complex map.
You can specify topics, sub-trees, or other maps within the parent
map as drop points.
Note: The drop points defined are active until you open another
map in the DITA Map view.