Does extending the hand to pick up something in front of the worshiper invalidate their prayer?

What is forbidden is passing in front of the worshiper, not merely obstructing with part of the body. This is based on the Prophet's (peace be upon him) saying: "(If any of you prays facing something that screens him from people, and someone wants to pass in front of him, he should push him away; if he refuses, he should fight him, for he is a devil)." 'A'ishah (may Allah be pleased with her) used to stretch her legs in front of the Prophet (peace be upon him) while he was praying, and he would not interrupt his prayer. Sheikh Ibn 'Uthaymeen emphasized that there is a difference between passing and lying down. If a woman lies down in front of a worshiper, it does not interrupt his prayer. Sheikh Ibn Baz also affirmed that extending one's hand to shake hands during prayer does not harm it.