private void add(PopupWindowPlacer next) {
		if (current == null) {
			current = next;
			head = current;
		}
		else {
			current.setNext(next);
			current = next;
		}
	}
Builds the final PopupWindowPlacer.
@return the PopupWindowPlacer
Ghidra/Framework/Docking/src/main/java/docking/widgets/shapes/PopupWindowPlacerBuilder.java