403 (Forbidden) - Error upon closing tab

[t68]

Hi!
After updating my shop to 2.6.14 from 2.6.6 I encoundered a strange problem.
In backend if I open settings for a payment method, pressing close gives me an error page: "403 (Forbidden) - Access denied" for the page http://www.mydomain.se/administrator/index.php . It also happens when I press Save&Close. But just Saving works fine.
I only encounter this error in on the Payment methods pages. Other pages in backend works fine afaik.
Frontend seems to be working fine.
The http://www.mydomain.se/administrator/index.php page has 644 permissions if i check it with filezila.
Thank´s for any input and help on this.

Setup: J2.5.28 - VM2.6.14 - php 5.3.29

[GJC Web Design]

I have seen this on a couple of sites . not exactly on this page but the difference between a save and Close and a save.

As these have been clients sites haven't bothered to look further.. (wasn't hired for that but told client)
My suspicion is that the save and close is triggering  a server firewall exclusion setting - you could ask your host if they see any blocking triggered with your ip address.