Isn’t this in fact expected since admin areas are intentionally not themed, e.g. we don’t allow admin to be broken by theming as it becomes impossible to fix it because you need the admin UI to work in order to change anything about theming in the first place?
Also, isn’t the trivial workaround to… simply avoid switching themes in the admin area?
Possibly, but if that is the case, then the option to switch themes should disappear when you navigate to admin, but it doesn’t so I am able to switch themes here. It is only after doing it that it disappears, so it looked to be an omission rather than a safety issue.
yes, and this may be an edge case. I was testing a possible issue with column headers not appearing (or rather being white on white) so wanting to see if the reported issue was theme-related - i.e. some OTHER setting was breaking the admin interface when it should not. So there will be some possible occasions where you might want or need to, but one could keep switching out of admin to do this, but since the option appears here, others may experience the same