Swapping between maps jiggles the selected layer and groups

@kunal649 is already working on this.

Since Mar 16, 2026.

### Problem

When I am moving around multiple maps and copy/pasting pieces as source material and I swap back to the target map I find all the groups closed and the layer I was on forgotten and instead replaced with a "best guess" at a layer with the same name.

```
Map A:
- Group1
- Objects
- ActualTarget <-- this layer is selected
- Group0
- Objects

Map B:
- Group1
- Objects <-- this layer will be selected in order to copy objects
```

Swapping between `Map A -> Map B` and swapping back to `Map A` after selecting some objects from `Map B` it places me in `Group0/Objects` when I return to `Map A` instead of `Group1/Objects`, not that it matters because I had selected the layer `Group1/ActualTarget` before I left `Map A`, intending to paste there.

### Goal

I want to be able to edit multiple maps simultaneously with complex group structures and copy/paste between them onto different layers without having to constantly find the layer I was previously on.

1) Remember the open/closed status of group layers when switching maps
2) Remember the selected layer when swapping between maps
3) If none of the above, make a better guess at the layer including group structure?