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?

What would you expect SkyDemon to do in this case? Would you like us to implement some sort of screen where you nominate your destination airfield? I hope you can see that would be an unwelcome intrusion for the vast majority of cases.

How far away was your Alternate from your Destination?  Perhaps it should switch approach options to the closest airfield?  

‌‌e.g.
1‌) fly overhead alternate - approach tools open for alternate
2‌) continue flying past alternate towards destination - When closer to the destination than the alternate, switch approach tools to the destination

I‌ could see this still being an issue if the 2 airfields are close together‌ though, so you'd need to disable switching if they're close together.  Maybe you could simply add an 'Open approach tools' option to the "What's Here" menu for airports, as a manual override.  It could help for en-route diversions too...

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.

That's pretty much exactly how it works already.

I think you are describing an edge case where you're overflying your alternate in pretty much a direct line before you get to your destination? What is the problem with removing your alternate when you know you're going to your destination, at which point SkyDemon would offer you all the normal approach tools? ‌‌

OK, it's a workaround!
Nevertheless it would be advantageous if the alternate remains in the pilot log until landing at the destination is assured...

I don't know if it was an edge case.
Airport B was LKCB and airport C was LKKV.
Is far as I remember, the wrong LKCB approach was persistent active until I reached VRP B of LKKV.

Or, in the event the situation is as described - when you press make approach - have an initial pop up box which says

‘Do you want to make approach at
A destination airfield X
B alternate airfield Y’

I agree the system shouldn’t force you and lock you out of what you want to do, unless it has been manually instructed somehow that you’re diverting.

Either way I think that this feature could be enhanced to make it useful in any case....