Airbus FCU - FMA Relation

[TheBusFlyer]

Good morning,

I had a question on the VS knob: when we push VS knob in CLB, DES, OP CLB or OP DES, the plane will level-off.

1) On FMA, VS= 0ft/min appears?
2) If I was in CLB or DES, when I push VS knob, the small white dot next to the altitude on FCU dissapears?
3) Is ALT still armed on FMA after pushing VS knob?

Thanks a lot.