Hei, was thinking: what is better from user perspective:
- The form which if not filled with all mandatory fields the "next" button is disabled
- The form with "next" button enabled, but after clicking it not filled inputs will be red?
Background of the problem: user is filling the form (has "next" button disabled") and aborts filling, after some time he comes back and sees the form in the list with the status "needs more information" and clicks on it, then in my opinion it's better to show him red inputs (so he will find easy all mandatory inputs he didn't fill) and disabled "next" button. But it's kinda different logic, why we are not showing the red inputs while filling the first time (now first time fill is with only disabled "next" button, red fields can't be displayed because user don't have click to action).