>I wanted the bottom edges of all my forms to line up so the nav buttons at the bottom of each one would also "line up". The .Height of each form was different. I wanted Form.Height + Form.Top = 401. I would change the value of .Top in design mode and find it changed back to 0. Why is that? Is it because the _SCREEN container doesn't exist in design time?
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>I solved it by making a new form property and putting THIS.Top = THIS.nProperty in the form.Init. Is that how form.Top is usually set?

You have a .Top property that may not be set to zero at design time. Also look at the AutoCenter property. Set it to false.