Whats with zac efron and ashley tisdale? r they going out? zac keeps posing with ashley. did he break up with ?

vena? i mean it looks suspicious. and there r so many rumors out there! whats the truth? is he going out with ashley? i heard a rumor thats hes going to break up with vena after hsm 3 is out. is that true? if it is whos starting it? who wants to break up zac or vena? just curious!! cause zac and vena r such a cute couple!!