I had Online Update bring in new versions of these packages recently and it was back to broken again, so it doesn’t look as though the bug report has generated much of a response. I wonder if that’s partly because the bug mentions only version 12.2. Is there an easy way to update the bug to refect multiple versions? Or perhaps I should create a new bug that refers back to the old one?
No need to open a new bug.
Just set the product to “openSUSE 12.3” below the “Additional Comments” field, when you add a comment (before you click on “Commit”).
I myself don’t use VNC since years ago, but if I find some time I may setup a server and try to investigate this further… But this has to wait till July or August I’m afraid.
And btw: another workaround would be to set the environment variable “QT_X11_NO_MITSHM” to 1 (maybe in your ~/.profile). Then an update to libqt4 won’t harm you anymore. 
Okay, took me a while :), but I’ve done that. Thanks for the QT_X11_NO_MITSHM hint. Will give that a go.