I don't believe the state for paletteMode and setPaletteMode (we use a different naming convention for controlled props anyway) should be owned by DashboardLayout. It's owned by the theme and if the user wants to manipulate it useColorScheme should be used. For the classic theme, I believe we should create a useColorScheme shim (i.e. rewrite useStandardPaletteMode with the same signature as useColorScheme and export from the library).

Ok, it was just a first idea and I wasn't sure about the names for these 2 props either.
We can go with that, the only disadvantage I guess is that it will only work with MUI theming (nevermind, the theme is strongly connected to the component anyway so this should be more automatic, sounds good!)

I was looking a bit more into this and not sure about the approach to take.

1. User is using DashboardLayout inside an AppProvider with any of the 3 theming methods we support (https://mui.com/toolpad/core/react-app-provider/#theming) => theme switcher already works
2. User uses DashboardLayout without AppProvider around it => we can make things work automatically if they're using a CSS vars theme by simply using the methods from useColorScheme, otherwise if they're using a standard theme it can only have one mode unless they're managing the active theme state themselves somehow, in which case we can't support it automatically?

About the shim, what scenario are we trying to solve with it? For internal components we have this context https://github.com/mui/mui-toolpad/blob/ad9bddb719a81cd113b73e82d304ae5ead1a0e8c/packages/toolpad-core/src/DashboardLayout/DashboardLayout.tsx#L81

Should I make an abstraction around the context as a hook that users can import called useColorScheme?

Ok, we could make it a dumb controlled property. But name it colorScheme, onColorSchemeChange to match naming of the cssvar theme, and also we always use onXyzChange for controlled prop xyz, not setXyz