We deployed the change to make it intuitive (similar to what is suggested) yesterday. It's still in integration branch so awaiting merging in main on this.
> i thought perhaps it had executed the step, which the check mark indicating completion or success.
Noted.
> It wasn’t clear that it was an input box since it didn’t have focus, and it wasn’t clear that the check mark was a button.
Noted.
> It seems like it’s the “Data” field, although the name doesn’t make much sense.
It is indeed a dropdown list but we had hard-coded it for sandbox so user can't change the source of an existing step. It is changeable when you host your own version or when you add a new step in sandbox.
> There’s a “reload”(?) icon next to it, but I have no idea what that does.
In case user decides to add a new source on-the-go (say in another tab), reload helps fetch the same list again.
Overall, I do understand that some parts of it are unintuitive and is a focus area for us to improve it asap.