Starting in alpha 9 whenever you click the eraser in the tile pallete as you try and erase tiles on the tilemap it will auto switch to paint brush without you selecting it or hitting the hotkey for paint brush. This is still in alpha 10. This only happens if you hold the eraser brush down so erasing multiple tiles in a row. If you single click it one tile at a time it stays on the eraser brush. This makes erasing tiles painstakingly annoying when you want to redo an tilemap or change a tile.