Dragging Item GUI

So i want to make Custom Inventory, do you know how to make when from custom toolbar drag the item above the inventory gui it will detect and move the tool to the inventory gui, so it’s like dragging from one gui to another gui

There is an open-source module made especially for this. You could have a look at the source and try to understand how it works. Although Im not 100% sure if this has snapping, but thats something you could look into.