The Keyboard module lets you play the selected sound at various pitches, depending on where you click on a piano keyboard.
If more than one channel is selected when you use this module, only the first selected channel will play.

If you click the “Change Pitch” button, the pitch of the sound will be changed to the one that corresponds to the last clicked piano key. To change the pitch of the sound, however, the module does not change the sound data itself. Instead, it modifies the playback rate.
So, if you don’t want the playback rate to be changed, you will have to do a “Resample Rate” effect on it, specifying the original rate.

Thanks to Hoby Van Hoose.