This bug report details an issue encountered with the Jenkins Role-Based Access Plugin. When attempting to define an Agent role in the Manage Roles section, the provided role pattern fails to identify matching agents.

Steps to Reproduce:

1. Access Jenkins and navigate to "Manage Jenkins."
2. Click on "Manage and Assign Roles."
3. Go to the "Manage Roles" section.
4. Create a new role or edit an existing one.
5. Under the "Agent" permissions, enter "master" as the role pattern.
6. Double-click on the "master" pattern.

Expected Behavior:

Double-clicking on the "master" pattern should display a list of agents matching the pattern (presumably an agent named "master").

Actual Behavior:

Double-clicking on the "master" pattern results in a message indicating "no agent found matching 'master'."