I'd recommend not doing this. What you are getting is the proper behavior with Windows. How will you handle this scenario: The user needs to edit the existing text, clicks into the text box, the cursor moves to the end of the text. They click where they want to edit, the cursor moves to the end? It will frustrate the users as it works differently than all other Windows programs.

>How do I ensure that when a user clicks on a text box, they are always at the farthest left position to begin typing? I dont want my users to begin typing in the middle of a text box.