Preheat the oven to 350 degrees F.
Combine confectioner's sugar, flour, and butter and process in a food processor until it forms a ball. Carefully remove the dough from the food processor and push the dough into a 12-inch tart pan (with a removable bottom). Make sure you press the dough fully into the indentations in the sides and ally he way up to the top of the pan. Make sure the crust is even.
Bake for 30 minutes. *At the 15 minute mark check to make sure the crust has not dropped on the sides. If it has carefully push the crust back to the edges using the back of a spoon. Remove from the oven and let cool.
While the crust is baking begging working on the glaze. Combine the thawed limeade, cornstarch, lime juice, and sugar in a small saucepan. Cook over medium heat until clear and thick, about 2 minutes. Remove from heat and let cool.
Using a stand mixer with a paddle attachment, beat the cream cheese, sugar, and vanilla together until smooth (about 2 minutes).
Spread the cream cheese mixture over the cooled tart crust.
Cut the strawberries into ¼-inch slices and arrange around the edge of the crust. Then line with blueberries, raspberries and another layer of strawberries. Place blackberries in the center.
Once the berries are arranged use a pastry brush, and lightly glaze the entire tart.
Refrigerate tart and remove 15 minutes before serving.