SD 3.8.2.72
iPad 4 mini

Situation: 3 Airports A, B, and C in one line.

Planned route is A to C with B set as alternate.

When overflying B, SD switches unwanted to approach for airport B and I had no chance to switch to approach for airport C!

Approach tools was not only useless in this approach, it also led to high workload when I tried to solve this unexpected situation without success.

How can I set the approach tools to the airport I want to land?

I'm used to follow good practice an try to be always ahead of the aircraft.

In this case it means to set up everything that can be done as early as possible and reasonable.
If I know the runway in use 10 min before landing from ATIS, I have plenty of time to set up the expected approach.

It drives me mad if a piece of software takes over control and forces me to do things at the totally wrong time.

Proposal:
Approach tools pop up at the selected distance from the planned destination airport C, regardless of B.
If I want to land on alternate B instead, I select airport B by tapping Route Direct B in the pilot log.

In general: approach tools are controlled solely by the next airport in pilot log.