qt.qpa.wayland: Minimizing not supported on wl-shell. Consider using xdg-shell

fresh install of Qt6 RC, yesterday; applied latest update few minutes ago.
running Chrome OS linux Debian Buster.

Created simple "Other/Qt Quick UI Prototype. initial values not changes.
Ran unchanged specification.

Received the following message several times in application output

qt.qpa.wayland: Minimizing is not supported on wl-shell. Consider using xdg-shell instead.

The min/max title controles do not work. See screen snapshot

In trying to solve the situation I found documentation on how to force xdg-shell,
in qt documentation.

I have modified the initial qml file to add include and reference to WaylandCompositer
with an attempt to follow the documentation (see screen snapshots)
But now the software objects to the XdgShell call.

Please fix the underlying situation and/or the WaylandCompositer documentation.