#2 Dmainwindow.ui has duplicate actionInit_Tutorial

[Bernhard M. Wiedemann]

Dmainwindow.ui contains two instances of actionInit_Tutorial that confuses Qt's uic tool enough to randomly chose one of them (unless ASLR is disabled) = https://bugreports.qt.io/browse/QTBUG-83186

The attached patch fixes the non-determinism, but needs testing if the intended functionality is still intact.