Thanks again for your responses!
To jzuidema:
Indeed, according to the "Reference" it should be #include <pitches.h> (without quotes around pitches.h). I think I tried that too, but I am not sure. I will try that again (but then I still wonder why the tutorial doesn't show it like that). And indeed, the .ccp file is missing. But the pitches.h file as shown in the tutorial is not a proper library at all and trying to make a .ccp file with it is not possible or too difficult for me (see my first post).
To PaulS:
As I stated, I use IDE version 1.0.4. I don't know what you mean by "dialog", but just above the window in which you type the statements of the program there are 5 buttons on the left side and 1 at the utmost right side. The first two utmost left buttons are round, the other 4 buttons are square. The buttons are (from left to right): Verify, Upload, New, Open, Save and Serial Monitor. So no button with a right arrow for New Tab.