app drag into a wpf window

Question

I want to write an wpf application which can do the followwing things:

I can drag a running application into the wpf application's window and it still works good;
The apps which has been dragged into can hide when the wpf application hide
The apps which have been dragged into can be drag back to the Windows desktop and still works

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I am new about it,and i want to know what knowledge should i study?