Why is there a "plus" icon at the … | Apple Developer Forums

Why is there a "plus" icon at the top right corner of my view?

I'm trying to implement the drag and drop feature to my LazyHGridview. When I try to drop the view on another view, a "plus" icon within a green circle is displayed at the top right corner of the view.

https ://i.ibb.co/J5cdhN7/Screen-Shot-2020-09-05-at-22-35-34.png

Code Block struct GridItemView: View {  var d: GridData
  @Binding var list: [GridData]
  @State private var dragOver = false
   
  var body: some View {
    VStack {
      Text(String(d.id))
        .font(.headline)
        .foregroundColor(.white)
    }
    .frame(width: 160, height: 240)
    .background(colorPalette[d.id])
    .onDrag {
      let item = NSItemProvider(object: String(d.id) as NSString)
      item.suggestedName = String(d.id)
      return item
    }
    .onDrop(of: [UTType.text], isTargeted: $dragOver) { providers in
       
      return true
    }
    .border(Color(UIColor.label), width: dragOver ? 8 : 0)
  }
}