We have tested it and can't reproduce it.  You could try uninstalling and reinstalling SmarterMail.  Are there any particular admin screens that it happens on consistently?

The only issue I have with the latest SM for any browser is, when a user clicks on another folder, it takes it awhile, like more than 3-10 seconds for the interface to refresh and update the folder listing/content.

 

Example, I click on delete folder going from my inbox folder, the little progress bar will flash, but nothing shows up for the delete folder.  Wait 1...2...3..4...5... 6... 7... then content list of the emails in the folder will show. It's ust not behaving normal for whatever reason. Using SM 12.4.5364 Enterprise, on w2k8r2

 

But the last time when browsers did something funky, I had to uninstall, reboot, then reinstall and it usually takes care of the problem.

 

But doing it this time didn't help.

It seems my issue is related to something else on the server.  I tested more with IE11 and it seems fine.