Apply the antialias settings w/o notify the observers.
diff --git a/qt4/demos/viewer.cpp b/qt4/demos/viewer.cpp
index a8f13cc..00af774 100644
--- a/qt4/demos/viewer.cpp
+++ b/qt4/demos/viewer.cpp
@@ -165,8 +165,8 @@
 
     m_doc = newdoc;
 
-    slotToggleTextAA(m_settingsTextAAAct->isChecked());
-    slotToggleGfxAA(m_settingsGfxAAAct->isChecked());
+    m_doc->setRenderHint(Poppler::Document::TextAntialiasing, m_settingsTextAAAct->isChecked());
+    m_doc->setRenderHint(Poppler::Document::Antialiasing, m_settingsGfxAAAct->isChecked());
     m_doc->setRenderBackend((Poppler::Document::RenderBackend)m_settingsRenderBackendGrp->checkedAction()->data().toInt());
 
     Q_FOREACH(DocumentObserver *obs, m_observers) {