HP Prime on Android - how to get the title bar back?

[mtern]

Hello,

I recently bought the Hp Prime for Android app.
I find it's excellent software but I have a little problem i can't get through.
If I hide the title in the calculator using the corresponding option in the calculator app menu, the whole layout improves and adapts best to the phone layout (I'm using a Galaxy S6+ edge).
However I didn't find a way to get the title bar back. A similar issue on the virtual Prime for Pc is solved right clicking with the mouse, that gets that menu on screen.
But with the android device I couldn't have a similar effect.
The only successful action was to drop and reinstall the app from the android market.
Probabily I'm missing some obvious point.
Anyone could help?

Thankyou.
Marco.