Grid settings

Composite frames work on a principle of best fit - they display the maximum number of portraits that need to fit into a given area in pleasing arrangement of rows and columns.
However, you can override the suggested layout and customize the portrait arrangement in the Editor's Layout tab.

Grid settings are available after adding a composite frame and setting its query.

Click on the  > button to expand the options:

Columns & Rows

Change the arrangement of rows and columns.

Move the slider to move it right/left to change the number of columns or rows, or click on the number value at the end of the slider to type in a new value.

After applying new rows and/or column settings, the grid will adjust to fit with the constraints of the composite frame's area.  

The composite frame will always try to show as large a portrait as possible while respecting the selected number of rows & columns. In the example below, the height of the composite frame is determining the size of the portraits displayed at five rows deep.

Row & Column spacing

To adjust the spacing between portraits, use the Horizontal & Vertical spacing options.

Move the slider to the right to increase the distance between the portraits.

In this example, the height of the composite grid versus the number of rows determines the size of the portraits. 

When the horizontal spacing is increased, the portraits have room to move over. When the vertical spacing is increased, the portraits must shrink to increase the gap between them.

Auto-Spacing

Click Auto Cell Spacing to maximize the row & column arrangement within the current composite frame area.
Auto Cell Spacing acts as a "make it fit" tool.

When the composite frame is resized while Auto Cell spacing is on, the portrait spacing auto-adjusts to accommodate the number of rows and columns to fill the frame.

Composite Frame Warning

If you select a row & column arrangement that does not accommodate the number of portraits required by the composite frame's query, the composite frame will display a warning. The Fix warning appears to warn you that the grid is "broken" with the current settings.
In the example below, the query results in 28 portraits that need to fit into the composite frame, but the rows and column setting only allows 20 to show. 

Click on the FIX warning to auto-adjust the number of rows and columns so all portraits can be displayed. Note the selected spacing value is not affected.

Reset to default

To reset any slider to its default value, double-click on it.