I have experienced this a few times developing a Nintex Forms when previewing a form I have just designed:
and I always ended up to delete some rules, re-create them, re-check all of them just to find which of my fields’ rule was not hidden by itself but would hide the whole form.
I just managed to repeat the issue several times and it just lays with a missing parenthesis in a rule formula (!)
Obvious but when you have dozen of fields and rules, it would be nice that Nintex Forms preview doesn’t load and simply returns an “error” rather than just a blank form, right ?
As I was creating a simple form for my client I created a control in Nintex Forms called “TRIM” standing for “HP TRIM” and I just need to make another hidden control appear when the tick box is selected, just as illustrated below:
To my surprise he didn’t work whatever I tested.
The rule formula to hide the controls were :
– hide when this is true: Not(TRIM)
After a while I realised that Nintex also provide a Runtime Function called “trim”
So renaming the check-box control to “TrimService” (no change to the connected SharePoint field) fixed it, and here is the correct Rule Formula below, so be careful that Nintex doesn’t have its own reserved words.