SSHSSH
You can check a couple of ways to see if a sig is in staging. Firstly, go to Attack Signatures on the left hand menu and then select Policy Attack Signatures. This will show all the signatures for the selected web application. If you change the filter to Custom you should be able to select In Staging - Yes and this will list all sigs within this web app that are in staging.
Second way is under Policy Building - click on Manual and I believe under the Traffic Learning section if you have sigs in staging you will have a link called "Attack signature staging" - if you click on this it will show up details of violations triggered against sigs in staging.
This is 9.4.8 ASM so may be slightly different depending on your version.
Hope this helps.
N