Officers have very broad discretion during traffic stops (and other citizen interactions) to assure their own safety. We may not like it, but for the most part it's quite legal. This was based on a Supreme Court ruling 40 years ago:
http://www.floridasupremecourt.org/e...feb/terry.html
Different LE agencies may have different guidelines for their officers (typically it varies based on the local political climate), but in any case the officer was within her legal rights to remove and control your weapon for the duration of the stop.
pax