The right mosue button is currently used for both camera control and selecting targets. In practice, this means that roughly every 3 camera moves, you select a new target (or deselect your current target), especially in crowded fights.
This is very frustrating at best, but gamebreaking at worst. Imagine duelling with someone and losing target just as you’re about to cast a spell. The spell still goes off, fizzles and they just got a free dodge.
Seeing as how we can ALSO target with left, I really don’t understand why this function should remain in the game.
If you can read this then it is proof that ArenaNet’s moderators just, kind and fair.