WPF Popup with TextBox doesn't save text when clicking outside of Popup

Question

I have a WPF UserControl containing a Popup which contains a TextBox. There is a DependencyProperty associated with the TextBox. The Popup has StaysOpen = "False". When I enter text in the TextBox and click inside the Popup then the text is persisted, as expected. If I click outside the Popup after entering text, then it is not persisted. Any ideas how to persist the text in this case?

Answer 1

A colleague of mine found a solution - by adding "UpdateSourceTrigger=PropertyChanged" to the binding.