I\'m sure this is something very simple but I can\'t figure it out. I\'ve searched here and on msdn and have been unable to find the answer. I need to be able to set the ric
Application.Current contains a collection of all windows in you application, you can get the other window with a query such as
var window2 = Application.Current.Windows
.Cast()
.FirstOrDefault(window => window is Window2) as Window2;
and then you can reference the control from your code, as in
var richText = window2.MyRichTextBox