如果弹出窗口相对于其放置目标移动了，我可以告诉代码隐藏吗？

I'm working on a WPF project where I have a grid of thumbnails (each thumbnail is a SurfaceButton), and clicking on each thumbnail shows its own popup menu. The popup menu in each case has its 'sibling' photo thumbnail as its placement target. The thumbnail and popup sit alongside each other in a Grid.I'm working on a WPF project where I have a gri