I took a look through reported issues and did not see one which matched your description above. As such I would suggest the following which might resolve this behavior:
1. Try a different browser
2. Clear out your browser's cookies and caches
3. If you are using an add-on/pop-up blocker temporarily disable it to see if this resolved the behavior
If these suggestions do not resolve the issue I would recommend opening up a case in your support group so that we can take a look at your instance directly and collect further information related to the scope of this behavior.