I opened an OpenFileDialog in the Flyout. How can I prevent the UI from freezing?

[huohuaing]

Hello everyone! I have a problem.
When opening an OpenFileDialog from within a Flyout, the entire UI freezes. The current solution is to close the Flyout before opening the OpenFileDialog. However, my View structure is in the following form.

Flyout A
└── UserControl A
└── Button A
└── Flyout B
└── UserControl B
└── Button B

How can button B obtain Flyout A and call its Close method?

[jyswjjgdwtdtj]

Maybe you can create a new Thread or Task and show your OpenFileDialog in it?