Why does drag and drop duplicate when i drag it?

I have an event that when you buy the item, it goes to the game layout and creates the object that you just brought. Then it goes to the layout and creates the object. You're suppose to be able to drag and drop the item you want. But when i drag it, it creates a whole another instance of the object. Someone said to put a variable and when it has been picked, destroy it. But since there are multiple instances of the objects how do you destroy just the one initially created? Or does anyone know any other way to solve this? Thanks!

Without a capx it's hard to know but, if your using a variable and it's in a constant state it would continue to trigger as long as the condition is being met. Try adding "System>Trigger once while True" on the condition or as a condition as a sub event.