How to set this animation for popupmenu in WPF?

[VahidEra]

Hi guys,
I have a popupbox in my project and I want it to have this animation when it opens:

I slowed the movie down so its animation is better visible:

I think two transparency and scale options have been used for this animation, the scale is created step by step and the value has not been suddenly transferred from 0 to 1, of course this is my guess.
I tried to produce this animation with the help of my dear friend @miloush, but I did not get the necessary result Because I only noticed the animation movements by slowing down the opening of the popup box. And I ask you to help me in completing this animation if you can. For your convenience, I have provided the project file below. Thanks for your help.

This is sample project

[miloush]

If you are using controls of a 3rd party library I think you should turn to them for support. I don't see how you can achieve this with PopupBox, but I am no expert on the library.

[VahidEra]

@miloush Dear Jan, yes, I got it. Thank you for your guidance.