The properties bar, the rectangular area immediately below the Dialog Editor's menu bar, displays the screen coordinates of the currently selected dialog or control. When a dialog is selected, as it is after you first click New from the File menu, there are also three edit fields on the properties bar:
The small solid rectangles around the dialog border are called resize handles. They show that the dialog is currently selected.
You can use the mouse to resize the dialog with the resize handles, and you can move the dialog with the arrow keys or the mouse. To move the dialog with the mouse, click and drag its title bar or border. The coordinates in the fields on the left side of the properties bar change as you move the dialog.
At times it may be useful to design the dialog in the graphical context in which it will be used. For example, you may wish to see how the dialog box looks against the backdrop of the application (the way users of your application will see it).
You can design the dialog box on the screen where it will eventually appear.