private void positionInSameGroup(ComponentPlaceholder newPlaceholder,
			ComponentPlaceholder relativePlaceholder) {

		// use the relative placeholder and the 'intra' group information for placement
		ComponentNode node = relativePlaceholder.getNode();
		WindowPosition intraGroupPosition = newPlaceholder.getProvider().getIntraGroupPosition();
		if (intraGroupPosition == WindowPosition.STACK) {
			node.add(newPlaceholder);
		}
		else {
			node.split(newPlaceholder, intraGroupPosition);
		}
	}
Finds or creates a component placeholder object for the given provider.
@param provider the provider for which to get an placeholder object.
@param defaultPlaceholder the placeholder to use if an existing one cannot be found
@return a component placeholder object that will be used to manager the providers component.
Ghidra/Framework/Docking/src/main/java/docking/PlaceholderManager.java