Overlay Panel with ngFor

[buseodaci]

Hi,
I want to use overlay panel with my button list. So every time overlay panel should be displayed bottom next button. But its not show up like i want, overlay panel appear same location even when i click different button. I tried using with [appendTo]="body" but also not work too.
This is my stackblitz : https://stackblitz.com/edit/angular-ebuae2