In an ungreased 13x9x2-inch (3.5L) baking pan, combine cherry pie filling, blueberries, raspberries, corn starch and 2T sugar; set aside. Stir together flour, 1/4 cup sugar, baking powder and salt. With pastry blender or 2 knives cut in butter until mixture is crumbly. Add milk; mix lightly with fork until just combined. Drop spoonfuls of batter onto fruit mixture. Bake in 375F (190 °C) oven 35 to 40 minutes or until browned and bubbly.