Second issue: after I select a ground cover and I run „Fill Entire Map” or „Fill Empty Tiles” nothing happens, although there is a message saying „Map Filled...”
Yes, thanks for having a call on Discord with me to clarify those things!:D
The conclusion was that the problems happened because of the "tile size" set, they have to match the size of the tile used (by default the textures TikeMaker DOT comes with are 200x200 px, so "tile size" should be 200 until the users switch the textures with their own)
It was nice talking to you, and good luck with your game in RPG Maker!:D