OpenFileDialog issue in FSI

Question

Simple question:

In F# Interactive, this does not work (it shows no dialog):

open System.Windows.Forms
let dlg = new OpenFileDialog()
let res = dlg.ShowDialog()

This code does work, after I first do a simple MessageBox:

open System.Windows.Forms
MessageBox.Show("Now it works!")
let dlg = new OpenFileDialog()
let res = dlg.ShowDialog()

This code also works, after first showing a Form:

open System.Windows.Forms
let frm = new Form()
frm.Show()
let dlg = new OpenFileDialog()
let res = dlg.ShowDialog()

This code however does not show any forms, not even the Messagebox:

open System.Windows.Forms
let dlg = new OpenFileDialog()
let res = dlg.ShowDialog()
MessageBox.Show("Now it does not work...")

It seems the OpenFileDIalog blocks on something, if it does not have some other form warm/ load something first, no idea what.

Any ideas what would make the OpenFileDialog work straight away?

Using Microsoft (R) F# 2.0 Interactive build 4.0.40219.1

Thanks, GJ

Answer 1

The windows are there, they just appear behind the Visual Studio UI, so it's easy not to notice them. I'm not sure why they do not appear in the foreground.

A quick test in FSI from the command line (i.e. not the hosted VS one) indicates the windows come to the foreground in this case.