@kevinlog FYI  We recently made a similar change in the Management area, but I think we hard-coded the zIndex value. I think this approach here (to use the values provided by `theme.eui.euiZNavigation` is better, so when we do refactor our implementation _(we wanted to make the change so that any `euiFlyout` in management automatically is set correctly)_ we use this instead \U0001f642 