So I replaced the Manifest Editor command:
SetApplicationAttribute(android:theme, "@android:style/Theme.Holo")
with this line:
CreateResourceFromFile(Macro, Themes.DarkTheme)
But this brings complete new behavior to the app. Transparent buttons are no more transparent and what is even worse, the piano keys come to foreground when pressed, which looks not really realistic and was not the case with the old manifest editor line (picture attached).
Any idea, what I could do?