Hi!
- That's weird, I've never seen such glitch before. Is it visible in the generator itself, not on the exported PNG? Could you send me an SVG file next time when you encounter it again?
- In the future desktop version of the generator it will be possible to customize how every element of map is drawn, but for the web version I'm going to keep using 4-colour palette. It's not hard to implement a way of specifying what are those 4 colours, but it won't help with your issue. You may want to try exporting maps to SVG though. I know that working with vector graphics may seem cumbersome, but there you can select objects/groups of objects precisely without worrying about antialiasing and similar things.