FUNCTION

This is a shorthand for MUIA_Group_HorizSpacing and MUIA_Group_VertSpacing, it sets both of these attributes at once.

Using MUIA_Group_Spacing, you won't need to think if your group is horizontal or vertical, both cases are handled automatically.

Note that setting a spacing value for a group overrides the user's default settings. Please use it only if you have a good reason.