Hi,
Please check the version of your EO.Web.dll. The current version is 2014 and should have a major version number 12. We have tested with the current version and it seems to work fine.
If you are using an older version, then please try to update to the latest build and see if it corrects the problem for you. What happens is browsers updates very frequently these days, so if you have an earlier version, then it may not work well with the latest browsers.
If the problem still occurs after you update to the latest build, then please try to isolate the problem into a test project and send the test project to us. You can see test project guidelines here:
http://www.essentialobjects.com/forum/test_project.aspxThanks!