Using group picker, alphabetic search order can create an inconsistent auto complete or don't find a group

When trying to search for a group which display name begins with the last letters on the alphabet and is present in another, as prefix, sulfix or in the middle of, user will not be able to select that group. That occurs because the default auto complete setting for JQL (Lucene) is to display only 20 records.
A workaround is set manually the configuration in the JPM.xml to a higher number, which will let user to find the group in a big list. However, that could reflect negatively in another JIRA behavior (performance, JQL default behavior and etc).

To reproduce that error, using an instance from the box:

• Create a new project
• Using a fake group called zzz, create at less 21 groups using that name in the middle, prefix and sulfix.

Ex:

8 group zzz - 8
9 group zzz - 9
Access 1 group zzz
access 11 group zzz -11
Access 2 group zzz - 2
Access 3 group zzz - 3
Access 4 group zzz - 4
Access 5 group zzz -5
Access 6 group zzz - 6
Access 7 group zzz - 7
Bet 19 zzz badges
Can 10 zzz group - 10
DB 16 group zzz
Fifteen zzz group
For sure zzz - 21
Force 13 group zzz - 13
Fourteen  group zzz - 14
Last 20 of zzz group
Next 12 group zzz - 12
Next zzz group 13
Under eighteen zzz group
XXX 18 zzz
zzz

• Edit the project roles
• Try to find and set the group zzz in any role

Only after change the auto complete default value, will be possible to find and select the group zzz.

Cheers,

Paulo Renato