我的画布纵向和横向拉伸，但里面的图像却没有。

I'm creating a popup menu a ToggleButton and a Popup control. All of which are contained within a canvas. The following image is of the bottom right corner of my application. I set my Canvas so that's in the Index 1 column, stretches 2 columns, and is in the second to bottom row.I'm creating a popup menu a ToggleButton and a