[2005] textbox auto selects all when window regains focus, how can I turn this off?

If I change the window focus on my application, say by selecting Internet Explorer, and then I go back to my application, all the text in the textbox is automatically highlighted. I went through all the properties but nothing seemed to change this. How can I turn this off?

It might help to note that on Text Changed, I have the text box copy to a text box on another form

maybe set the selectedtext property to string.empty?