Fluxbox and Zoom, How to get window decorations?

I use fluxbox as my window manager. All of my other applications, besides the Zoom video conference application has window decorations, and they can be toggled on/off with the appropriate fluxbox key binding/command. Zoom does not. I has space above it for window decorations, and when I toggle them on/off this space disappears and comes back, but it never has the window decorations in it. How can I fix this? In a related question, https://unix.stackexchange.com/questions/502964/how-to-force-enable-window-decorations-on-application , @Lars Kotthoff says this is a problem related to the fact that "fluxbox doesn't have a compositor." What is a compositor? How can one be used to solve this problem? (I don't need anything to be transparent, or have a drop shadow, which seems to be the primary function of a compositor, from what I've learned trying this so far.) As requested, some versions: $ fluxbox --version Fluxbox 1.3.7-gentoo-r4 : (c) 2001-2015 Fluxbox Team $ uname -a Linux kirk 4.19.44-gentoo #5 SMP PREEMPT Thu Mar 19 12:31:30 EDT 2020 x86_64 Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz GenuineIntel GNU/Linux $ eselect profile show Current /etc/portage/make.profile symlink: default/linux/amd64/17.0/desktop