ofxGui ofParameterGroup Events

what am I doing wrong here?

in ofApp.h:

void paramChangedEvent(ofAbstractParameter &e);

ofxPanel gui;
ofParameterGroup paramsA;
ofParameterGroup paramsB;

ofParameter<float> numA;
ofParameter<float> numB;
ofParameter<bool> toggle;

in setup:

gui.setup("gui");

gui.add(toggle.set("toggle", true));

paramsA.setName("params a");
paramsA.add(numA.set("num a", 0.5, 0, 1));

paramsB.setName("params b");
paramsB.add(numB.set("num b", 0.5, 0, 1));

gui.add(paramsA);
gui.add(paramsB);

ofAddListener(gui.getParameter().castGroup().parameterChangedE(), this, &ofApp::paramChangedEvent);

//...

void ofApp::paramChangedEvent(ofAbstractParameter &e) {
	cout << e.getName() << endl;
}

exposing parameters works. what about getGroup() or something?

ofAddListener(gui.parameters.parameterChangedE(), this, &ofApp::paramChangedEvent);

i’m not a 100% sure but i think this is a bug i recently fixed where that function, castGroup wasn’t really implemented