Fix missing tabfocus with manhattanstyle

I added a new focus rect for combo boxes
with manhattan style. To reduce the visual
impact I follow the same policy we use on
windows where we do not show the focus rect
unless it is called upon by tabfocus.

src/plugins/projectexplorer/miniprojecttargetselector.cpp

@@ -385,6 +385,7 @@ MiniProjectTargetSelector::MiniProjectTargetSelector(QAction *targetSelectorActi
     bar->setFixedHeight(panelHeight);
 
     m_projectsBox = new QComboBox;
+    m_projectsBox->setFocusPolicy(Qt::TabFocus);
     f.setBold(false);
     m_projectsBox->setFont(f);
     m_projectsBox->ensurePolished();