I can not stress enough how much this part of the UI sucks.
It needs reworking, but it especially needs a method for you to preview rewards from challenges. Jumping backwards and forwards between the Challenges menu Event tab and the Heroes menu to check what the rewards actually are is a really terrible experience. It’s just bad.
UI - You get an emote for Ana!
Me - Cool, what does it look like!
UI - An emote
Me - Wow, thanks! So helpful! /s
Yeah, it could be loads better.
Spoiler alert: they never fixed it.
The “Reward Preview” window in-game is still terrible. You can’t hear the voices, see the skins, sprays. They also show you 3/17 items on a page and you have to keep scrolling. I don’t really do the events, in part because of this.
I guess while I’m at it, the Battle Pass “Rewards” button that lights up at every new level still doesn’t highlight the new thing you just got. LOL?
Oh well. At least the cash shop is fully stocked. 
Funny thing i swear it used to work back in OW1. If you clicked on a reward it would take you to it. But now that the shop, hero screen etc is all mixed up I don’t think it works.