I have heard that in addition to the prohibition of passing in front of someone who is davening shemoneh esrei, it is also forbidden (or at least improper) to walk in front of someone who is saying kaddish. Does anyone know if this is true, and if so what the source is? Thanks.
Birkei Yosef (OC 56:9) equates passing in front of one who is saying Kaddish with passing in front of one who is davening the Amidah. He is quoted by the Ben Ish Chai (Vayechi 1, 10), and Sha'arei Teshuvah (OC 56:1).
Kitzur Shulchan Aruch Yalkut Yosef (56:9) brings this, as well as that some disagree.
Just like one does not walk in front of someone who is praying, so too one should not walk in front of someone who is reciting Kaddish. (Kitzur Shulchan Aruch of Rav Rephael Baruch Toledano, siman 12, laws of kaddish, seif 2; Ben Ish Chai (Vayechi, 10)