These parameters apply only to selected objects that are Applique objects.
All Applique parameters except one (color of tack-down stitches) are subset of the Column object parameters . Color of tack-down stitches is specific to Applique objects only.
Left: applique object with all layers. Right: layers moved to the side for better view.
Layer 1 is mark-up stitches. Their meaning is to show position of applique patch on the underlaying fabric.
Layer 2 is tack-down stitches. Their meaning is to fix applique patch on the underlaying fabric. They are separate color to force machine stop before and after this layer. Stop before tack-down allows to place applique patch on position idicated by mark-up stitches. Then the tack-down stitches are placed to fix the patch and the next stop allows to trim the patch along the tack-down stitches.
Layer 3 is cover stitches. They overlap and hide tack-down stitches and edges of the applique patch.
Note: in contrast to Column object, Applique cannot have gradient effect nor strips fill.