Let’s us a selectable List as follows:

import SwiftUI

struct ContentView: View {
    @State private var elements: Set<UUID> = [.init(), .init(), .init(), .init(), .init()]
    @State private var selection: Set<UUID> = []
    @State private var isConfirmationDialogPresented: Bool = false
    
    var body: some View {
        NavigationStack {
            List(
                elements.sorted(),
                id: .self,
                selection: $selection,
                rowContent: { Text(String(describing: $0)).lineLimit(1) }
            )
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    EditButton()
                }
                ToolbarItem(placement: .bottomBar) {
                    Button(
                        "Delete (selection.count) element(s)",
                        role: .destructive,
                        action: { isConfirmationDialogPresented = true }
                    )
                    .disabled(selection.isEmpty)
                    .confirmationDialog(
                        "Delete (selection.count) elements(s)",
                        isPresented: $isConfirmationDialogPresented,
                        actions: {
                            Button("Delete (selection.count) element(s)", action: {
                                elements = elements.subtracting(selection)
                            })
                        }
                    )
                }
            }
        }
    }
}

When tapping the Button to display the confirmation dialog, the selectable List is reset. How to prevent this?

Note: moving the .confirmationDialog to List causes the same behavior.

Tested with Xcode 16 beta 4 • iOS 18.