You should be able to use a placement environment variable and use onChange to detect a change of the variable. Place this in your ContentView @Environment(\.tabViewBottomAccessoryPlacement) var placement Then use onChange to detect the change between inline and expanded. However, it seems that this environment property might be broken as of now. I have attempted to use it to create custom views for the minimized/inline accessory with no success.

I ran into the same issue and found two solutions: Use a switch statement to exhaust the conditions for TabContent. This unfortunately results in the tabViewBottomAccessory always showing in every tab though, and as an empty accessory, which is not ideal. Create an extension to View that you can use to modify the conditions of that view: extension View { @ViewBuilder func `if`<Content: View>(_ condition: Bool, transform: (Self) -> Content) -> some View { if condition { transform(self) } else { self } } } Then you can use it as follows: TabView(selection: $selectedTab) { ... } .if(selectedTab == .storage) { this in this.tabViewBottomAccessory { Button { // Action } label: { Label("Add Item", systemImage: "plus") } } }