/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
var Gameplay = Container.expand(function () {
	var self = Container.call(this);
	var gameplayGraphics = self.attachAsset('gameplayBackground', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	return self;
});
var Tower = Container.expand(function () {
	var self = Container.call(this);
	var towerGraphics = self.attachAsset('testTower', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	return self;
});
var UI = Container.expand(function () {
	var self = Container.call(this);
	var uiGraphics = self.attachAsset('uiBackground', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000000
});

/**** 
* Game Code
****/ 
var draggedTower = null;
var isDragging = false;
var gameplay = game.addChild(new Gameplay());
gameplay.x = 1024;
gameplay.y = 1093;
var ui = game.addChild(new UI());
ui.x = 1024;
ui.y = 2459;
var buttonBG = game.addChild(LK.getAsset('BGbuttonTower', {
	anchorX: 0.5,
	anchorY: 0.5
}));
buttonBG.x = 1024;
buttonBG.y = 2600;
var puntero = game.addChild(LK.getAsset('Puntero', {
	anchorX: 0.5,
	anchorY: 0.5
}));
puntero.x = 1024;
puntero.y = 1366;
puntero.alpha = 0;
var dragButton = game.addChild(new Tower());
dragButton.x = 1024;
dragButton.y = 2600;
dragButton.down = function (x, y, obj) {
	isDragging = true;
	draggedTower = game.addChild(new Tower());
	draggedTower.x = 1024;
	draggedTower.y = 2600;
	draggedTower.alpha = 0.7;
};
// Game move handler for dragging
game.move = function (x, y, obj) {
	puntero.x = x;
	puntero.y = y;
	if (isDragging && draggedTower) {
		var offsetX = 0;
		var offsetY = 0;
		var gameplayLeft = gameplay.x - gameplay.width / 2;
		var gameplayRight = gameplay.x + gameplay.width / 2;
		var gameplayTop = gameplay.y - gameplay.height / 2;
		var gameplayBottom = gameplay.y + gameplay.height / 2;
		var gameplayCenterX = gameplay.x;
		var gameplayCenterY = gameplay.y;
		var distanceFromCenterX = Math.abs(x - gameplayCenterX);
		var distanceFromCenterY = Math.abs(y - gameplayCenterY);
		var maxDistanceX = gameplay.width / 2;
		var maxDistanceY = gameplay.height / 2;
		var normalizedDistanceX = distanceFromCenterX / maxDistanceX;
		var normalizedDistanceY = distanceFromCenterY / maxDistanceY;
		var maxOffset = 200;
		var offsetMagnitudeX = maxOffset * normalizedDistanceX;
		var offsetMagnitudeY = maxOffset * normalizedDistanceY;
		if (x >= gameplayCenterX && y <= gameplayCenterY) {
			offsetX = offsetMagnitudeX;
			offsetY = -offsetMagnitudeY;
		} else if (x <= gameplayCenterX && y <= gameplayCenterY) {
			offsetX = -offsetMagnitudeX;
			offsetY = -offsetMagnitudeY;
		} else if (x <= gameplayCenterX && y >= gameplayCenterY) {
			offsetX = -offsetMagnitudeX;
			offsetY = offsetMagnitudeY;
		} else if (x >= gameplayCenterX && y >= gameplayCenterY) {
			offsetX = offsetMagnitudeX;
			offsetY = offsetMagnitudeY;
		}
		var targetX = x + offsetX;
		var targetY = y + offsetY;
		var uiTop = ui.y - ui.height / 2;
		var uiBottom = ui.y + ui.height / 2;
		var uiLeft = ui.x - ui.width / 2;
		var uiRight = ui.x + ui.width / 2;
		if (targetY > uiTop) {
			targetY = uiTop - 50;
		}
		if (targetY < gameplayTop) {
			targetY = gameplayTop + 50;
		}
		if (targetX < uiLeft) {
			targetX = uiLeft + 50;
		}
		if (targetX > uiRight) {
			targetX = uiRight - 50;
		}
		var uiTopCheck = ui.y - ui.height / 2;
		var uiBottomCheck = ui.y + ui.height / 2;
		var uiLeftCheck = ui.x - ui.width / 2;
		var uiRightCheck = ui.x + ui.width / 2;
		var pointerInUI = puntero.x >= uiLeftCheck && puntero.x <= uiRightCheck && puntero.y >= uiTopCheck && puntero.y <= uiBottomCheck;
		if (pointerInUI) {
			if (draggedTower.tint !== 0xff0000) {
				tween.stop(draggedTower, {
					tint: true
				});
				tween(draggedTower, {
					tint: 0xff0000
				}, {
					duration: 200
				});
			}
		} else {
			if (draggedTower.tint !== 0xffffff) {
				tween.stop(draggedTower, {
					tint: true
				});
				tween(draggedTower, {
					tint: 0xffffff
				}, {
					duration: 200
				});
			}
		}
		var smoothness = 0.15;
		draggedTower.x += (targetX - draggedTower.x) * smoothness;
		draggedTower.y += (targetY - draggedTower.y) * smoothness;
	}
};
// Game release handler
game.up = function (x, y, obj) {
	if (isDragging && draggedTower) {
		var gameplayLeft = gameplay.x - gameplay.width / 2;
		var gameplayRight = gameplay.x + gameplay.width / 2;
		var gameplayTop = gameplay.y - gameplay.height / 2;
		var gameplayBottom = gameplay.y + gameplay.height / 2;
		var uiTop = ui.y - ui.height / 2;
		var uiBottom = ui.y + ui.height / 2;
		var uiLeft = ui.x - ui.width / 2;
		var uiRight = ui.x + ui.width / 2;
		var uiTopCheck = ui.y - ui.height / 2;
		var uiBottomCheck = ui.y + ui.height / 2;
		var uiLeftCheck = ui.x - ui.width / 2;
		var uiRightCheck = ui.x + ui.width / 2;
		var pointerInUI = puntero.x >= uiLeftCheck && puntero.x <= uiRightCheck && puntero.y >= uiTopCheck && puntero.y <= uiBottomCheck;
		var towerInUI = draggedTower.x >= uiLeft && draggedTower.x <= uiRight && draggedTower.y >= uiTop && draggedTower.y <= uiBottom;
		if (pointerInUI || towerInUI) {
			draggedTower.destroy();
		} else if (draggedTower.x >= gameplayLeft && draggedTower.x <= gameplayRight && draggedTower.y >= gameplayTop && draggedTower.y <= gameplayBottom && draggedTower.y >= gameplayTop) {
			draggedTower.alpha = 1.0;
			draggedTower.tint = 0xffffff;
		} else {
			draggedTower.destroy();
		}
		isDragging = false;
		draggedTower = null;
	}
};

===================================================================
--- original.js
+++ change.js
@@ -1,5 +1,10 @@
 /**** 
+* Plugins
+****/ 
+var tween = LK.import("@upit/tween.v1");
+
+/**** 
 * Classes
 ****/ 
 var Gameplay = Container.expand(function () {
 	var self = Container.call(this);
@@ -119,8 +124,36 @@
 		}
 		if (targetX > uiRight) {
 			targetX = uiRight - 50;
 		}
+		var uiTopCheck = ui.y - ui.height / 2;
+		var uiBottomCheck = ui.y + ui.height / 2;
+		var uiLeftCheck = ui.x - ui.width / 2;
+		var uiRightCheck = ui.x + ui.width / 2;
+		var pointerInUI = puntero.x >= uiLeftCheck && puntero.x <= uiRightCheck && puntero.y >= uiTopCheck && puntero.y <= uiBottomCheck;
+		if (pointerInUI) {
+			if (draggedTower.tint !== 0xff0000) {
+				tween.stop(draggedTower, {
+					tint: true
+				});
+				tween(draggedTower, {
+					tint: 0xff0000
+				}, {
+					duration: 200
+				});
+			}
+		} else {
+			if (draggedTower.tint !== 0xffffff) {
+				tween.stop(draggedTower, {
+					tint: true
+				});
+				tween(draggedTower, {
+					tint: 0xffffff
+				}, {
+					duration: 200
+				});
+			}
+		}
 		var smoothness = 0.15;
 		draggedTower.x += (targetX - draggedTower.x) * smoothness;
 		draggedTower.y += (targetY - draggedTower.y) * smoothness;
 	}
@@ -135,11 +168,19 @@
 		var uiTop = ui.y - ui.height / 2;
 		var uiBottom = ui.y + ui.height / 2;
 		var uiLeft = ui.x - ui.width / 2;
 		var uiRight = ui.x + ui.width / 2;
+		var uiTopCheck = ui.y - ui.height / 2;
+		var uiBottomCheck = ui.y + ui.height / 2;
+		var uiLeftCheck = ui.x - ui.width / 2;
+		var uiRightCheck = ui.x + ui.width / 2;
+		var pointerInUI = puntero.x >= uiLeftCheck && puntero.x <= uiRightCheck && puntero.y >= uiTopCheck && puntero.y <= uiBottomCheck;
 		var towerInUI = draggedTower.x >= uiLeft && draggedTower.x <= uiRight && draggedTower.y >= uiTop && draggedTower.y <= uiBottom;
-		if (draggedTower.x >= gameplayLeft && draggedTower.x <= gameplayRight && draggedTower.y >= gameplayTop && draggedTower.y <= gameplayBottom && !towerInUI && draggedTower.y >= gameplayTop) {
+		if (pointerInUI || towerInUI) {
+			draggedTower.destroy();
+		} else if (draggedTower.x >= gameplayLeft && draggedTower.x <= gameplayRight && draggedTower.y >= gameplayTop && draggedTower.y <= gameplayBottom && draggedTower.y >= gameplayTop) {
 			draggedTower.alpha = 1.0;
+			draggedTower.tint = 0xffffff;
 		} else {
 			draggedTower.destroy();
 		}
 		isDragging = false;