Hello, I have a richtextbox that I am to be able to type in, I want to be able to select the text and flip the case of the selected string. So... "hello world" would magically be "HELLO WORLD". Here is what I currently have, it does not work, but it does not spit any errors at me. Any ideas? Code: private void lowerCaseToolStripMenuItem_Click(object sender, EventArgs e) { RichTextBox rtb = (RichTextBox)tabs.SelectedTab.Controls[0]; ; rtb.SelectedText.ToLower(); } Thanks