Format Style dialog won't come up.

I'm sunk because the Format Style dialog box won't come up. It doesn't even come up for a blank score. Since rebooting doesn't help I reinstalled MuseScore 3 and still can't get the Format Style dialog box.

Steps: Format Style.
Result: Nothing. Program seems frozen until you press Esc or Enter. Apparently, the dialog box is there but hidden, but I can't find it even across two screens or when I use -D to force Musescore to shrink.

Where is the Format Style dialog box and how can I get it back?