If You stretch a bow (to the limit) and throw a ender pearl it disappears (Creative Mode)

You need to be in Creative Mode. (hold all the time right-click (for drawing the bow and throw the pearl)) If You stretch a bow, but do not shoot, and then switching the slot to a ender pearl you throw it but do not get new, as with snowballs or eggs

(sry, english i'snt my native language ;-D)