it does not seem to me that the textbox is getting the focus:
"Create a new Folder",
"Please enter the name of the new Folder:",
Closed = (
object sender, WindowClosedEventArgs e) =>
if (true == e.DialogResult && !string.IsNullOrEmpty(e.PromptResult))
string folderName = e.PromptResult;
Is it possible to active the OK button only when text has been entered?