Hi friend!

Sometimes I use the properties in code, such having the left and top properties set in the form Load event, this way I make myself sure that the position of this child form will be the one I set, but other common problem is, without a doubt, to asign it in design mode and when it goes run time, they will try to fit under MDI, which is the main idea of a child form, but try that, and if you can also use the resize method to set these properties, much better!

I hope this can help you amigo!