Hot off the press, Application Express version 3.1.2 has just been released.
The link to the direct download is here, if you’re upgrading via the patchset on Metalink then the patch number is 7313609.
You can find more details about the patch here.
There looks like quite a few fixed bugs (it’s always hard to say that without it sounding like a bad thing!) in this release, definitely worth the upgrade!