System.Windows.Primitives.Popup - Can't refocus to TextBox after clicking another Window

_This issue has been moved from [a ticket on Developer Community](https://developercommunity2.visualstudio.com/t/SystemWindowsPrimitivesPopup---Cant-/940323)._

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In my WPF application I have a Popup whose StaysOpen="True". Works great. On my Poup is another UserControl that contains TextBoxes, ComboBoxes, Buttons, etc.

When I show the Popup using, MyPopup.IsOpen = true; from the code behind of my application it is displayed as I would expect.

While the Popup is open I navigate to any other application, use Windows Notepad as an example. I start typing in Notepad and then return to my WPF application whose Popup is still being displayed. This is the behavior I want to see.

Here lies the problem. If I click the TextBox on the Poup my application seems to **never be notified that the focus has been set on the TextBox.** If I start typing after clicking on my Textbox the characters are added to the open Notepad application. This behavior happens no matter which "other" application I open and/or select while my Popup is displayed. The only way to overcome this problem is to close the Popup by clicking my close button on the Popup. For whatever reason Buttons are not affected by this strange behavior.

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### Original Comments

#### Feedback Bot on 3/6/2020, 11:56 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

#### Feedback Bot on 4/10/2020, 03:54 PM:

I have detected that for the last 35 days, this issue didn't have much product team activity and a very small amount of new votes or comments. Based on this, its severity, and affected area, it’s my experience that this issue is very unlikely to be fixed.

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### Original Solutions
(no solutions)