Ubuntu 23.04: can't send (some) windows to back

[Paul Smith]

This release Ubuntu 23.04 is the first one in a very long time (and
I've been using Ubuntu since pretty much the first releases) that I'm
serious considering dumping and going back to something older.  I
upgraded to it because I have a brand new laptop and I was hoping to
get some improved support.  But I'm having so many annoying problems.

The most egregious one for me is that many apps don't obey send-to-back
(mouse middle-click) or bring-to-front (mouse left-click) on the title
bar anymore.  I can bring-to-front by left-clicking in the application
window itself (but that moves my cursor), but clicking on the title bar
does absolutely nothing.

This is not true for ALL apps.  For example Chrome still works, and
Gnome apps like file manager and gnome-terminal, but it doesn't work
for xterm, or Evolution (although my Evolution is installed from
flatpak), or third party apps like Slack etc.

Of course I have checked that my mouse bindings are still set (and as I
said it does work for some apps).  I am using X11, not Wayland.  This
was working fine with 22.04 and 22.10.

What is going on?  I can't find anything about this on Google.