I was arrested for a felony and 4 misdemeanors in PA in 2003. The charges were withdrawn (felony & one misdemeanor) and nolle prosequi for the remaining charges at the outset of trial.
It came up at the GE interview (2013) and NEXUS (2014) CBSA background check. As long as you can show the charges were dropped with paperwork, you will have no problem being approved.
In fact, neither officer cared about the details of the charges, only that I was not convicted of anything and could prove it.