Can select button in PM, not in ZP

[shabbysquire]

In latest 5.7 build, I'm able to favourite a Fiverr gig in PM ok (button changes to 'favourited'). But in ZP nothing happens.

I've tried various ways to target the button, and nothing works in ZP. I've even put pause in ZP and manually click, but again, nothing registers - the button doesn't even change state. All proxies are dedis and are fast.

Any tips?