This was supposed to be only windows.

See commit d0340ee0,
which breaks it for Mac at least.

src/plugins/qt4projectmanager/qt4projectconfigwidget.cpp

@@ -59,7 +59,9 @@ Qt4ProjectConfigWidget::Qt4ProjectConfigWidget(Qt4Project *project)
 
     // fix the layout
     QAbstractButton *browseButton = m_ui->shadowBuildDirEdit->buttonAtIndex(0);
+#ifdef Q_OS_WIN
     browseButton->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+#endif
     m_ui->gridLayout->addWidget(browseButton, 4, 2);
     int minimumHeight = qMax(m_ui->qtVersionComboBox->sizeHint().height(), m_ui->manageQtVersionPushButtons->sizeHint().height());
     Qt::Alignment labelAlignment = Qt::Alignment(style()->styleHint(QStyle::SH_FormLayoutLabelAlignment));