Yes, it's actually a cancel zap instead of a real undo. It just looks like an undo for UX reasons. 

I just assumed the recipient wouldn’t be notified until the 5 seconds were up. @ek can you clarify?

WeAreAllSatoshi

Oh, good to know. Don't think I'll enable it though. Reversible transactions are so fiat.

gnilma

It's in the settings. If you enable it, you get like 5 seconds to rescind your zap.

I found it kind of irritating, because I like to change pages quickly and that was messing up my zaps.

Stacker Saloon

saloon

It's in the settings. If you enable it, you get like 5 seconds to rescind your zap. 

I found it kind of irritating, because I like to change pages quickly and that was messing up my zaps.