By default, data is displayed view in one column for each panel in the Details view. You can define that data is displayed in two columns (= in a grid). If the Grid view is enabled, empty fields are always displayed.

You can also define a placeholder that you can add to the Grid view (e.g. if you want that a specific field is always displayed as the first field in a line, you may want to define an empty placeholder). Add a field to the desired panel and set the Empty field attribute. This field is then "displayed" without label and without content.