The Map Chunks dialog gives a list of all the map chunks that can be used within the
map. A map chunk is an 8x8 set of tiles that represent a commonly used combination of
tiles. The map is then made up of combinations of these chunks, rather than individual
tiles. Whilst this saves space, it does produce limits on the possible combinations that
can be used, since there are only 1024 chunks available. It is well to keep this in mind,
as drag-and-dropping ground shapes from a Graphics Editing window onto a map will change
the chunk at that map position, affecting all uses of that chunk within the map.
To edit a particular chunk, double-click on it. A chunk editing window will be opened,
showing each individual shape within the chunk. It's tiles can be changed by
drag-and-dropping shapes from a Graphics Editing window onto the particular position
whose tile you want to change.