There has been no progress that I can detect on solving this problem.
Its been raised a number of times in this forum under different titles
(searching for 'blank' finds some).
I've commented on my experiences to date in a few forum topics,
and raised a bug, plus added comments on another bug. I raised
the bug as high priority as it renders most email unreadable for
a lot of people.
Alas, so far I have had no luck in attracting the attention of any developers
on this one - I suspect that they dont even know its in there.
If anyone knows a Roundcube developer that they can tap on the sholder
to point out this problem, I'd really appreciate it.
(I have had a go myself but no luck so far)
Cheers.
Paul