Is it possible to move main menubar down?

[wysota]

Did you try simply using QMainWindow::setMenuWidget() and passing a complex widget composed of your custom data and a QMenuBar laid out vertically?

+-------------------+
|QWidget w. v-layout|
| +---------------+ |
| | CUSTOM WIDGET | |
| +---------------+ |
| |    QMenuBar   | |
| +---------------+ |
+-------------------+

+-------------------+
|QWidget w. v-layout|
| +---------------+ |
| | CUSTOM WIDGET | |
| +---------------+ |
| |    QMenuBar   | |
| +---------------+ |
+-------------------+

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Edit: Note that it's available since Qt4.2. In earlier versions you have to stick with mangling with the layout directly.