Sounds like you have started your map from the CC3 dungeon template instead of DD3 dungeon. CC3 dungeon is a cut-back style intended for people who owns CC3+, but not DD3 to be able to create basic dungeons. This template does indeed not contain the Flagstone G fill. It is possible to add it, but you are probably better off just starting a new map in the DD3 Dungeon style.

A very nice map.

You may want to reduce the text size in the legend a little bit though. I notice how some of it basically touches the right edge, and due to the fact how true type fonts behave, they may stretch more at certain zoom levels, so having a buffer avoids the risk of the text extending over the border at those zoom levels.

Great work Quenten. It's a lovely map.

Apart from the tiling effect on the water, I also noticed the road fill looks a bit weird, at least when the map is exported at this scale.

I don't think there is a built in option, but those commands are just macros, so you can easily set up your own using the TOGL command on the layers instead of SHOW and HIDE.

Have a look at the final part of this article ("troubleshooting" heading) for a bit more on the macros, it should give you enough info that you can construct a toggle macro yourself:

Colors aren't changed immediately when you move the house to a new layer. You then need to use the color buildings option in the City menu, this will recolor all the buildings based on their current layer.