Textbox scroll to caret

Question

please see code, Im trying to dynamically add three text boxes to a tabpage, i need each texbox to scroll down to the end of the page as text from a pipestream comes in, currently only the last textbox being created will do this so i presume something is being overwrote in memory but im not sure how to do tell each textbox to follow the same routine

SendMessage(pipeTextBox.Handle, WM_VSCROLL, (

IntPtr)SB_BOTTOM, IntPtr.Zero);