Terminal: Add Shell option menu

Change-Id: I08ea3c52ed28ab65f2dc902051bab9e6975e6a7e
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/coreplugin/manhattanstyle.cpp

@@ -189,6 +189,12 @@ int ManhattanStyle::pixelMetric(PixelMetric metric, const QStyleOption *option,
     int retval = 0;
     retval = QProxyStyle::pixelMetric(metric, option, widget);
     switch (metric) {
+#ifdef Q_OS_MACOS
+    case PM_MenuButtonIndicator:
+        if (widget && option->type == QStyleOption::SO_ToolButton)
+            return 12;
+        break;
+#endif
     case PM_SplitterWidth:
         if (widget && widget->property("minisplitter").toBool())
             retval = 1;