style = LayoutStyle.getInstance();
int west = style.getContainerGap(todrop, SwingConstants.WEST, container);
int h = container.getHeight();
if (Math.abs(tx - insets.left) < THRESHOLD_DISTANCE) {
List<Quartet> list = new ArrayList<Quartet>();
Quartet trio = new Quartet(insets.left, insets.left, insets.top, h - insets.bottom, new VerticalLeadingContainerAnchor(container));
list.add(trio);
return list;
} else if (Math.abs(tx - west - insets.left) < THRESHOLD_DISTANCE) {
List<Quartet> list = new ArrayList<Quartet>();
Quartet trio = new Quartet(west + insets.left, west + insets.left, insets.top, h - insets.bottom, new VerticalLeadingGapContainerAnchor(container));