Yet another question... as regards the Giant Reach scenario.

I'm tracking the SR-71 (target No 1301) with the use of IADS. But then I changed my mind and I wanted to track another target, for example 1306, 3203 or 3304. But it seems impossible. I clicked the red buttons of AC3, V-MD, D-MD, CZU VKL, etc., but I can't track another target. Can't move the speed gate or change radar bearing.
I even switched to the KI-2202V panel ('W') and started to move the switches from GOTOV and POLN to VYKL, to no avail.
The radar was still working.
Pressing the red buttons - no effect (except for the second from the left, of course).

Well, maybe I'm doing something wrong. So:
- is it possible to shoot down any other plane in this scenario?
- is it possible to switch to another target and track it with the use of IADS?

No more questions so far