public static void LogMessage(string message, ConsoleColor consoleColor) { MainForm.Instance.Invoke( new MethodInvoker( delegate { var messageColor = consoleColor.DrawingColor(); int length = MainForm.Instance.richTextBox1.TextLength; // at end of text MainForm.Instance.richTextBox1.AppendText($"> {message}\n"); MainForm.Instance.richTextBox1.SelectionStart = length; MainForm.Instance.richTextBox1.SelectionLength = 5 + message.Length; MainForm.Instance.richTextBox1.SelectionColor = messageColor; MainForm.Instance.richTextBox1.SelectionLength = 0; })); }