Impersonate: The Impersonate button becomes disabled

Issue Summary

Usability issue: the Impersonate button becomes disabled if keystrokes are used to select a user for impersonation

Steps to Reproduce

1. Browse to Impersonate User slide-out
2. Start typing in the name of the target user
3. Use the arrow keyboard keys to select the user
4. Hit ENTER to select
5. Notice the blue Impersonate button becomes disabled

Expected Results

• The user is selected then is impersonated
• A mouse click behaviour should have the same behaviour as a keyboard selection.

Actual Results

• The Impersonate button becomes disabled and impersonation is no longer possible.

Workaround

• If the mouse/mice is used to select the user's name, then the button remains active.