Placing tree tiles deletes surrounding grass tiles — help?

Hi! I’m using GameMaker Studio 2 and I’m placing PNG tree tiles into my tilemap, but whenever I place them, it deletes or resets the tiles underneath (like my grass tiles). I read that there’s a “Clear Tiles” option I need to uncheck, but I can’t find it anywhere.





Here’s what I’m doing:

• I select a few tree tiles to make a brush.
• When I place them, it wipes out other tiles on the same layer.

Any help finding the right checkbox or setting would be really...

Placing tree tiles deletes surrounding grass tiles — help?