I'm having a similar issue with the popover not anchoring to the correct view. I can tell that it's initiating but I can't get the popover to show from within a tab view. I played with the z-index of the popover wrapper but it didn't seem to fix the issue. Is it a issue with chrome? I'm testing on a android device with default chrome browser. The CodePen example also seems to have the same issue when in Chrome? I would like to use $ionicPopOver instead of $ionicModal because of my UI design. Note I'm not using the ion-tabs directive but the tabs css classes. I'll go back to $ionicModal for now because I don't have the time to solve this issue but it would be nice for the future.
Neve mind I solved the issue. $event was getting mutated somewhere along the line and I resolved the issue.