QOpenGLWidget update() doesn't render scene when multisampling enabled - c++

Question

I'm trying to use anti-aliasing to get shaper edges in my scene. However, when I enable multisampling and I call QOpenGLWidget::update() the scene doesn't update. Although if I click on the scene then an anti-aliased scene is rendered. If I comment out the one line setting the number of samples used then an aliased scene is rendered as normal when calling update.
I set the default surface format in main.cpp I'm using CoreProfile 4.3 with samples set to 4.
#include <QApplication>
#include "widgets/mainwindow.h"
int main(int argc, char *argv[])
{
auto format = QSurfaceFormat();
format.setVersion(4,3);
//If I comment out this line everything works great but with jagged edges
format.setSamples(4);
format.setProfile(QSurfaceFormat::CoreProfile);
QSurfaceFormat::setDefaultFormat(format);
QApplication a(argc, argv);
MainWindow w;
w.show();
w.resize(1200, 800);
return a.exec();
}
In my viewer.cpp which inherits from QOpenGLWidget I enable GL_MULTISAMPLE
QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
f->glEnable(GL_MULTISAMPLE);
An example (there are many more) that doesn't render when I call update when using multisampling is when I load in a new mesh.
auto ViewerWidget::importMesh(QString filename) -> void
{
mesh = new Mesh(filename);
initializeGL();
update();
}
However, when I click on the screen then the scene does update. My mouse movement events are below and don't do anything special compared to my mesh import method.
void ViewerWidget::mousePressEvent(QMouseEvent *event)
{
if (event->buttons() & Qt::LeftButton) {
m_rotationTrackball.push(pixelPosToViewPos(event->pos()), m_scaleTrackball.rotation().conjugate());
}
update();
}
void ViewerWidget::mouseReleaseEvent(QMouseEvent *event)
{
if (event->buttons() & Qt::LeftButton) {
m_rotationTrackball.release(pixelPosToViewPos(event->pos()), m_scaleTrackball.rotation().conjugate());
}
update();
}
void ViewerWidget::mouseMoveEvent(QMouseEvent *event)
{
if (event->buttons() & Qt::LeftButton)
{
m_rotationTrackball.move(pixelPosToViewPos(event->pos()), m_scaleTrackball.rotation().conjugate());
}
else
{
m_rotationTrackball.release(pixelPosToViewPos(event->pos()), m_scaleTrackball.rotation().conjugate());
}
update();
}
Any suggestions on how to solve this would be appreciated! Thanks in advance.