This a work-a-round solution, but it is effective.
You must be running either Chrome or Firefox with Adblock Plus.
Add the following filter rule to Adblock Plus under “Preferences” in Firefox:
In Chrome, select “Options” in Adblock Plus and click on the “Blacklist” tab. Click the “Edit” button, add the line of code and then click “Save.”
Close and restart Chrome or Firefox.
The instant preview should now be disabled.