Evolution: Content appears blank

After updating, evolution 3.44.4 has become unable to display the content of any mail.
It appears to have reduced the display area for mail content to full-width but zero less than one line height; so the content is hidden from view. I’m guessing there may be a stale file that needs to be removed from somewhere under .local/evolution/
Any assistance would be appreciated

Hi,
I suppose you also updated WebKitGTK, to a version which begun to
ignore frame flattening option, which they left in the API, but it does
nothing in reality. That causes what you see.

Either update the Evolution, the current stable series is 3.54.x (your
version had been released more than two years ago, on 2022-08-05, while
the other dependencies made changes incompatible with the old code) or
downgrade the WebKitGTK version to the one you had installed before the
update.

If your distro does not provide a newer Evolution, you can try for
example a Flatpak version, which has its downsides, but it’s better
than nothing for long term support distros. It can be found here:

Bye,
Milan