Changing issue status does not work on Opera

On Opera:

1. On an issue, I press Workflow => "on hold"
2. I press the "Change" button, and then the content si loaded with html mark up (see capture), the change buton is disabled and an infinite loading wheel appears
3. After a page refresh the issue's status is not changed

On chrome, it works as expected:

1. On the same issue, I press Workflow => "on hold"
2. On the popup I press "Change"
3. The issue's status is correctly updated