How do I use the NewGen -> Extension -> Edite Tileset Feature?

Hi,
whatever I do there, it saves the map but doesn't change anything at all. Even if I load the map again. What am I doing false there? And I can exceed the Tile Set Cap with it or not?

You can add up to 16, but you can't exceed it above that.

So, when you've selected all the tiles that you want in the dialog, you click ok -> the map saves.
Directly after that you do File->Close Map (don't do anything else in between).
Now you can re-open your map and it should update your terrain tool with the new tiles.

Thanks I'll try.

Edit: Yai got it \o/