Not to be offtopic o.o but I kind of wish there was a way to remove targeted marked, too - like the ground targets window have 'x' to get rid of all of them. I sometimes mark frozen people in Scylla - both party and alliance - so they're easier to see, but I'd like to just clear that off the person once they're up and running off. Mainly for alliance peeps - I found them hard to target when they're running amuck in the chaos. I end up to targeting scylla and pressing the same target sign again, twice, to wipe the slate.
Unless there's something I'm gravely missing. >.>;

I guess an idea to get around both of these is to assign the ground/target marks IDs that lead back to your character so only you can wipe/move them o_o