I have a xaml file MyTB.xaml with a TextBox:

<Window
xmlns="[link:schemas.microsoft.com]">
<TextBox>Please type something in me</TextBox>
</Window>

I build that with the following in fsi:

#light

#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0";;
#r @"PresentationCore.dll";;
#r @"PresentationFramework.dll";;
#r @"WindowsBase.dll";;

open System
open System.Windows
open System.Windows.Markup
open System.Windows.Controls
open System.Xml

let createWindow (file: string) =
using (XmlReader.Create(file)) (fun stream -> (XamlReader.Load(stream) :?> Window))

let window = createWindow("MyTB.xaml")

window.Show()
window.Topmost <- true;;

The weird thing about the TextBox that gives me is, I can delete characters (with backspace), and I can enter spaces, and I can copy text from the clipboard, but I can't enter any character other than a space from the keyboard. Am I missing something here? If I tweak the F# (by adding a function to instantiate an Application, and running the Application) I can compile an executable that has a perfectly functional TextBox, so I don't think I'm missing a library, or need to add some kind of event handler.