We were using OpenLayers 2.7 before and everything was working fine. Then we decided to upgrade our system to use OpenLayers 2.10.
We have popup positioning issue with this new version. The popup is getting displayed away from the actual marker. It is working fine if I roll back to use OpenLayers 2.7.
I can not insert a snap here but you can have a look at the examples below. Ref. http://dev.openlayers.org/releases/OpenLayers-2.10/examples/popupMatrix.html
I guess there is not an integration issue in my system/code as it's working fine with OpenLayers 2.7. Ref. http://dev.openlayers.org/releases/OpenLayers-2.7/examples/popupMatrix.html
I checked it with all browsers, the behavior is same for all.