private void detachChild() {
		if (child == null) {
			return;
		}

		child.parent = null;
		child = null;
	}
Restores the component hierarchy from the given XML JDOM element.
<p>
The process of restoring from xml will create new {@link ComponentPlaceholder}s that will be
used to replace any existing matching placeholders.  This allows the already loaded default
placeholders to be replaced by the previously saved configuration.

@param rootNodeElement the XML from which to restore the state.
@return the newly created placeholders
Ghidra/Framework/Docking/src/main/java/docking/RootNode.java