Path for a program that selects its textbox automatically

I have a program that has a bug. It has a textbox that whenever you write in there it automatically selects all of its content at a random time. So what is happening that when I write in that textbox in the middle of the writing its selects every thing and the next character I press it deletes everything =\
Im new to autoit so please help me to write a code that will recognize when the text is selected and just puts the cursor at the end of the text.