Random reveal
If you think you are revealed, look to see if the icon is in the buff bar. Just because you see yourself, doesn’t mean you are ‘revealed’.
If 2 forms of stealth are placed on you at the same time, it shows your character to you when one of them ends, but not to others unless all your ‘stealth’ is gone. I have not tested it between veil/mi/decoy (because I didn’t use stealth much on mes before I played thief a lot, edit: I actually did notice that decoy will cause you to see your character with veil and vice versa), but I know if a thief applies a stealth to you and you mi (or vice versa…), when one ends, you ‘appear’ to be revealed, but you are not. Be very aware of Shadow Refuge, walking out of that instantly puts the ‘Revealed’ on you and that will remove your stealth and of course prevent any being applied as well.
edit: Also, as stated below, Ranger skill Sic ’Em will reveal you. So would a stealth trap
(edited by Lunacy Solacio.6514)
I’m assuming this is in a pvp scenario? Be it spvp or wvw. It could also be a ranger tagging you with Sic ‘Em. It’s rare that a ranger will actually use it but it’s quite lethal against classes that rely on stealth (thief/mesmer). Additionally, as the animation for Mass Invis is so obvious, it would not be hard to tag you or another important target with Sic ’Em before it finishes casting.
I’ve grown quite fond of the skill simply because other players do not expect it. I sometimes wonder if they also think something has bugged when, after tagging them with Sic ’Em, they proceed to spam one stealth skill after another, hoping that one of them will work.