[Elecraft] AF Knob lockout during keypad frequency entry (FW 5.14 and lower)

[Bob]

There may be a reasonable reason why the firmware locks out the Audio Gain
Control during keypad frequency entry, but today that gotya caused me teeth
to hurt -- I had been listening to a weak DX station on 15 CW, so the AF
gain was pretty high.  I decided to move to a different frequency, and had
just pushed the buttons to start entering the new frequency, with a very
strong/loud signal popped up right where I was listening.  My hand shot to
the AF gain knob, which I discovered was locked out.  So I was stuck with
way too much audio until I managed changed to a new frequency, at which
point the AF control was re-enabled.

Is there a reason why the AF control is locked out during keypad entry of a
frequency?

73, Bob, WB4SON