Form Location Settings StartPosition properties

There are the following options, respectively, meaning the following:

The Centerparent form is centered in its parent form.
The Centerscreen form is centered in the current display window and its dimensions are specified in the form size.
The position of the Manual form is determined by the Location property.
The Windowsdefaultbounds form is positioned in the Windows default location, and its boundaries are determined by Windows by default.
The WindowsDefaultLocation form is positioned in the Windows default location, and its dimensions are specified in the form size.

Centerscreen does not mean that the screen is centered (relative), it is centered in the current display window.

You should select Centerscreen when using the show () method, and the form progress bar can be used

The

Use the ShowDialog () method should select Centerparent so that the window to be displayed is centered, and the active form is the popup form.