I'm currently using Pitbull for unitframes. The issue I'm running into is when I click on a target my target unit frame shows but when I tab to another target and tab back my target frame is gone yet I can still attack the target. I have done some research and it looks like it's affecting X-Perl as well as Pitbull. Can anyone shed some light on this issue for me. Thanks.
I know this kinda sounds like a run of the mill Blizzard answer, but have you tried deleting or renaming your WTF folder and then updating the addon? If you go to a fresh WTF and AddOn and it still continues, it may be something wrong with the game. Also, try doing it with the default WoW unitframes and see if it continues.
This seems to happen for me when no target is selected when I enter combat. If I select myself and keep myself selected when combat starts, I'm able to get a target frame for other things. It's like the targetframe doesn't exist until I have something targeted and Blizz's stoopid UI won't build a new window in combat.