Reference choice list using AJAXReferenceChoice doesn't display all choices?

[frankh_]

I am stuck.   I built a series of reference fields to a table to build a cascading list of drop down choices, each dependent on the next:

Tier 1

Tier 2

Tier 3

I set the attribute on the first field as ref_auto_completer=AJAXReferenceChoice and as a drop down choice with none.

For the tier 2 and three the attributes are ref_auto_completer=AJAXReferenceChoice,ref_qual_elements=u_tier_1 and ...tier_2 respectively.   I created a client script to clear 2 & 3 on change of the proceeding fields.

All appears to work well until tier 3.   in one cascading series I have 22 possibilities for tier 3.   Only 14 display.   glide.ui.max_ref_dropdown is set to 25.

What has me stumped is that if I convert tier 3 back to a list, instead of a drop down choice all 22 possibilities display in the list - so I don't see how it can be reference error.

Does anyone have any idea why / how AJAXReferenceChoice would further filter a list of choices to reduce the number of choices?   Is there another attribute that I need to set on the dictionary entry?

[frankh_]

Anyone have any ideas?

[frankh_ · Accepted solution]

So I got the answer to my own question - it is controlled by a system property - the article is here:   Customizing Choice Lists - ServiceNow Wiki

the actual system property is glide.xmlhttp.max_choices which is set to a default of 15 - which is why I saw 14 choices and --none--.