Incorrect results for custom field quick search

Summary

Custom field page had a new look and feel introduced in Jira 7.12. Also added was a quick search box.

However, using the quick search may return results that are not related to the search string as the search incorporates results from screen name as well. In other words, the search is not limited to custom field name.

Environment

This is reproducible on a vanilla instance

Steps to Reproduce

1. Create a screen. For example 'CustomizedUniqueScreen'
2. Create 2 custom fields. For example 'CustomField' and 'NothingRelatedHere'
3. Associate both the custom fields to the new screen
4. Go to Jira Administration > Issues > Custom field
5. Search with the word Custom or custom or partial word cus
6. Verify the results

Expected Results

Only custom fields with the name that has the string Custom or custom or partial word cus should be returned

Actual Results

Custom fields 'CustomField' and 'NothingRelatedHere' are returned (based on the above example). This is due to the 'NothingRelatedHere' field was associated to a screen with the name that contain the search string

Workaround

Ensure screen names are unique