I am aware this is reason of very strong contentions and heated conversations, and I will not enter in the merit of discussing the pros and cons of the switch in theming enacted by the GNOME development team, and now picked up downstream by XFCE developers with XFCE 4.16.
(this article, and especially its footnotes, will explain more about it and link all relevant conversations)
What I want to accomplish with this post is helping users like me who are not happy with the current looks of the desktop, cannot avoid one or two GNOME apps for their daily work, and yet would like to keep the theming consistent.
This very nifty workaround will restitute consistent theming to the XFCE software impacted by the update and the few GNOME apps using CSD on your system.
with a simple
yay gtk3-nocsd-git installation.
xfce4-settings-editor and in
xsettings set Gtk>DIalogUseHeader as false (untick box), to make sure the file picker is brought back to its former glory.
If you have any other tips, please feel free to share!!
Enjoy computing, the way you like it!!