I use the PuTTY terminal emulator and when I try to use the function keys whilst animating a program they do not work as they should.
In particular the F2 key should toggle between the program code and the program output, but the key press has no effect at all.
In PuTTY configuration, select Terminal ->Keyboard and note that the default setting is ESC[~. This needs to be changed to VT100 . The anim function keys will then work as expected.