How to do vertical reverse direction operation for ContentSizer?

[qian-o]

As the title, I want to achieve a reverse operation in the vertical direction, but I don't know how to achieve it.

Desired effect:

1.mp4

Actual effect:

2.mp4

The former I used the GridSplitter control, and the latter I used the ContentSizer control because there is only one control in the Popup.

[michael-hawker]

@qian-o can you share your XAML you're using? It looks like you set the Orientation on the ContentSizer control? But there's also the IsDragInverted property, as the ContentSizer doesn't know which direction you're trying to expand the target control in.

[qian-o]

Thank you for your reply, it seems that I don't understand the usage of the control enough.