Mac OS X 10.9 was released yesterday. When I ran my Qt 4 app on 10.9, the text alignment in the controls was broken. Here is the fix:

Qt Code:
  1. #ifdef Q_OS_MACX
  2. if ( QSysInfo::MacintoshVersion > QSysInfo::MV_10_8 )
  3. {
  4. // fix Mac OS X 10.9 (mavericks) font issue
  5. // https://bugreports.qt-project.org/browse/QTBUG-32789
  6. QFont::insertSubstitution(".Lucida Grande UI", "Lucida Grande");
  7. }
  8. #endif
  9.  
  10. QApplication a( argc, argv );
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More details at:
http://successfulsoftware.net/2013/1...0-9-mavericks/

I hope that helps someone.