Selecting image in Add priority dialog throws an error in console

Issue Summary

This is reproducible on Data Center: yes
Reproduced on 9.4

Steps to Reproduce

1. Go to Administration -> Issues -> Priorities
2. Click Add priority to open Add new priority dialog
3. Click select image

Expected Results

Some dialog/view shows up that allows to select some predefined priority image

Actual Results

Nothing happens in the UI. In the console the error is being thrown:

Uncaught ReferenceError: openWindow is not defined
onclick <baseURL>/secure/admin/ViewPriorities.jspa:1

Workaround

There is no other known way to select an image through the UI. Providing directly the icon URL can be treated as workaround.