All browsers are adding _blank to all links

Hi,

I have a site that I have been asked to do some work on (upgrading it from WP 2.5 to 3.1.2). So I have duplicated it on the server to work on and edited my host file like I have done in the past, to force my mac to see it.

Everything is fine development & upgrade wise but for one big issue. ALL the links open in a new window/tab! However when I view the source code there is nothing on the target??

Apart from upgrades to WordPress core & plugins everything is identical. I have deactivated the plugins to make sure they aren’t to blame. Sure enough they aren’t. They both are on the same server, so setups are the same too.

This happens on all browsers and both on a PC & Mac. Does anyone know why??

Thanks