Each oscillator has a button to enable keyboard tracking (Kbd. Track). This shuts off and turns on the oscillator's response to your master keyboard's (or the Sequencer's) pitch.
When you have two oscillators playing at the same time, one can be set to drone "pitchlessly" while the other oscillator plays tones against it. You can still tune the "drone" oscillator using the Oct, Semi, and Cent arrow buttonsbut it won't respond to your keyboard or to the Sequencer.
To turn off Osc 2 keyboard tracking