  A single-particle multi-branched wave-function is studied. Usual which-path
tests show that if the detector placed on one branch clicks, the detectors on
the other branches remain silent. By the collapse postulate, after this click,
the state of the particle is reduced to a single branch, the branch on which
the detector clicked. The present article challenges the collapse postulate,
claiming that when one branch of the wave-function produces a click in a
detector, the other branches don't disappear. They can't produce clicks in
detectors, but they are still there. An experiment different from which-path
test is proposed, which shows that detectors are responsible for strongly
decohering the wave-function, but not for making parts of it disappear.
Moreover, one of the branches supposed to disappear may produce an interference
pattern with a wave-packet of another particle.
