Since we don't even allow adding object constraints her while in Pose Mode, this tab is entirely pointless while in Pose Mode, and only serves to confuse. The Properties are meant to be context sensitive, so it makes sense to only see Bone Constraints while in Pose Mode:
|Open||None||T56950 UI Paper Cuts (Parent Task)|
|Resolved||William Reynish (billreynish)||T61559 Hide Object Constraints Properties when in Pose Mode|
@Brecht Van Lommel (brecht) Yes, we could do that too. That current warning box does seem clumsy.
I think that, given the fact that you can also adjust object transforms and related things while in Pose Mode, we could also just make both object and bone constraints available normally, as before.
If our Properties was more context sensitive, it could be different, but for now I agree with you.