I challenged a friend the other day. After the challenge was created, other than the message box confirming it, there was no way of knowing I had done that at all.
I have a problem with this behavior: it could be the case that I may want to cancel an outstanding challenge, but as it turns out, you can’t, because it doesn’t appear anywhere. It is also possible that I may want to know if a challenge is still outstanding or not, for whatever reason, or how many I have and with whom.
This is not the case with open challenges, which appear on the play page. I think it is important that personal challenges should also appear in a conspicuous place, with basically the same options as open challenges.
PS: Before the latest update, such challenges were indeed visible. I will assume there was an oversight here.