Gotchas about Drawloop that are not specified in their documentation and that I only find out through support tickets. So I'm writing them up here so everyone can know about them.
...
Note: There may be a fix for this coming soon! Yay! NO SIGN OF THIS FIX YET AND I DOUBT IT WILL EVER HAPPEN NOW THAT NINTEX OWNS DRAWLOOP.
SOQL
See the help documentation here
Filters
Filters are sooo powerful, and probably very underutilised because the new Nintex help documents are so basic.
Here's my real-word scenario:
I am trying to create a filterType with "contains" and it is not working as expected.
I have 3 documents that need to come from the one LOOP button (of course I could create multiple LOOP buttons but that defeats the purpose - I HATE multiple buttons, and the DDP page is quite good for choosing which document you want).
I want the three documents to be available depending on different stages of the Opportunity, combined with other values.
I created a text formula field (DocStatus__c) and have it return the following values depending on the status and other field values.
Invoice
Invoice;Terms
Terms;Status
Terms;
Status
I have 3 documents that need to come from the one LOOP button (of course I could create multiple LOOP buttons but that defeats the purpose - I HATE multiple buttons, and the DDP page is quite good for choosing which document you want).
I want the three documents to be available depending on different stages of the Opportunity, combined with other values.
I created a text formula field (DocStatus__c) and have it return the following values depending on the status and other field values.
Invoice
Invoice;Terms
Terms;Status
Terms;
Status
...
SELECT id FROM Opportunity WHERE ShowDocs__c LIKE '%Terms%'
However, the LOOP button will NOT show me this document unless ShowDocs equals exactly "Terms" it will not show this document if ShowDocs contains Terms in any other combination.
I have tried various combinations
Invoice Terms
Invoice, Terms
Terms Invoice
Terms, Invoice
Terms;Invoice
Nothing except Terms on it's own will work.
The response back from Drawloop support was surprising.
The button filter criteria is comparing the field value to the value in the DDP. So in this case it is checking if 'Terms Voucher' is contained in 'Terms'. So the button filtering method may not work for your use case
Wow! How is this not build to work like SOQL???!? Flabbergasted.
OK, I can beat this thing! 
Here's how....
In the Filter in the DDP I entered\
"Invoice" OR "Invoice;Terms" OR "Terms;Invoice"
It worked! 
I could have put
Terms Invoice;Terms Terms;Invoice
and it would have worked too . The filter fields ignore the "" and the OR but it just reads better that way.
...