为什么插入符号突然集中在编辑字段中？

I have a "username" TEdit on a Delphi 2006 login form. When the application starts up the user is asked to enter the username. The TEdit gets focus and the caret is placed in its horizontal center for some reason. As soon as anything is typed the caret is left aligned again and everything looks normal. I have a "username" TEdit on a Delphi 2006 logi