Textbox doesn't lose focus when clicking outside of it when inside Popup?

Question

I am working on a Windows 8.1 Store App using Windows Runtime.

I have a UserControl which holds a StackPanel which holds a number of TextBoxes.

When I place the UserControl on a Page and When I place the user control in a Popup I get different focus behaviour for the TextBox controls.

UserControl on Page: When I click on a TextBox it is focused, when I click outside the TextBox on it's parent (StackPanel) the TextBox loses focus.

UserControl in Popup: When I click on a TextBox it is focused, when I click outside the TextBox on it's parent (StackPanel) the TextBox does not lose focus.

What I want is for it to behave the same in the Popup as it does when on the Page.

What is causing this behaviour when the UserControl is in a Popup and how can I get it to behave the same as it does on the page when in the Popup?

Answer 1

It likely has something to do with the z-index of the popup. I think you should try to detect when the mouse is clicked outside of the popup and change focus at that time.