Might be a bug with drawVertices

in ofMesh drawvertices() seems to draw one less vertex than is in the mesh:

void ofApp::setup(){
    for(int i = 0; i < 4; i ++){
        for(int j = 0; j < 4; j ++){
            ofPoint p(i * 100, j * 100, 0);
            mesh.addVertex(p);
        }
    }  
}

//--------------------------------------------------------------
void ofApp::draw(){
    cam.begin();

    ofSetColor(255);
    for(int i = 0; i < mesh.getNumVertices(); i++){
        ofDrawSphere(mesh.getVertex(i), 3);
    }
    ofSetColor(0);
    mesh.drawVertices();
    cam.end();
}