Using tab targeting doesn't work when you're trying to target a friendly to buff their shields. --; Clicking on the nameplates works fine when you're on a team, but if you're in a public zone not so much.
That happens to me too sometimes, I'll target someone either by left clicking on them OR using tab and it will target the nearest ship but only for a split second before going to another ship further away. I've got my options set to target my attacker but that doesn't always work either.
This problem is made worse by the fact that changing combat mode (attack, defense, speed, balanced) breaks target. It would be nice to realize that one is taking to much damage and switch to defense mode and not lose target.