To adjust the position of the location

When you open a page in Internet Explorer, When the alert window pops up, it doesn't exactly show the same location in the middle I need to fix it, but I don't know what to do.

The page where the alert window appears is Previously, steps 1, 2, 3, and 4 were set to come out when they disappeared

I set the alert window to appear when the last step page appears.

What should I do with this source...