Why is my WPF textbox “kinda” readonly?

Question

I have a text box in WPF that is part of a datatemplate for a listbox. In that text box I can delete, backspace, spacebar, but I can NOT type in new words, letters or number

Answer 1

I created a simple test app, and I can type new text into the TextBoxes in the ListBox:

The only difference that I can see between the two is that an ItemTemplate is set on your ListBox, and one isn't on mine. What is the XAML for rADetailEntryLayout?