I was so used to the layout of the menus in the earlier version (1.10.x), where you could just click Tickets and all the open, unanswered tickets were listed. If I wanted to see a answered or closed, I had to choose them in another menu.
Then when I upgraded to 1.12.3, I started to get so confused when working on tickets. Suddenly both unanswered and answered appeared when I clicked the open ticket menu and I had to choose the sub menu of "Open", to see the unanswered ones. Then I found the settings for the queues.
I'm not completely sure what I did, but something with the table header broke. So I tried to set the settings back, but the table headers are still empty.
Looks like this now: 
But the Open/open still works and looks like this. 
I've only changed settings available in the control panel and I have not done anything with the code.
EDIT: Oh, I noticed I've placed this in the wrong forum part. Should have been in Troubleshooting and Problems