I am sorry to hear that this is happening within your account. There could be a few causes for this, so we would need to troubleshoot further to try to determine what the cause of this issue is. Can you please respond to this post with the answers to the following questions, so that we can better assist you:
- What browser/version are you using?
- Do you have another browser to test? Did using a different browser help?
- Can you try optimizing your browser, then closing all browser windows and re-opening?
- You mentioned seeing this when clicking on Contacts, do you see this happening anywhere else in the account?
- If possible can you get a screenshot of what you are seeing?