Firefox - constant resend popup?

[bs27975]

Kubuntu 12.04LTS, new install.

On most localhost/zm pages, clicking save within firefox returns:

Code: Select all

Confirm

To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier.

Cancel    Resend

I have to hit cancel then go to the address bar and hit enter to get back to a normal page. F5 (refresh) just enters the cycle again. More than once I've ended up with duplicate entries as hitting resend does ... what it says it does.

Any idea what's going on / what setting I've got that is causing this behaviour?