That little keyboard changes the front end's tuned frequency. Since it is 10 MHz wide and you made a small change the receiver can both remain active and as expected on the same frequency. All that little keyboard does is change where your receiver is within (or outside of) the front end's 10 MHz bandwidth. You can define multiple receivers each with a different tuned frequency. That is you can listen to repeaters on 448/060MHz and 448.000 MHz and 446.040 MHz all at the same time if your front end is (nominally speaking) anywhere between 443.060 MHz (about 443.6 MHz to avoid strange effects) and 451.060 MHz (again 450.4 MHz would be better). All three receivers would remain running on their tuned frequency. One thing you will notice is the bottom of the waterfall will show a shift in its frequencies an the active bandwidth when you tune with the little keyboard. That would show the effect I mean.

I don't know if I found the right words to explain. If not I'll try again.

{^_^}