Originally Posted by ppr:kut
What Qt widget style are you using? I got the same when I tried oxygen-transparent. Apparently the screenlocker doesn't take transparency too well, so if your theme used it too, you can try switching to one that doesn't.
I thank you for your input, but I believe I have found what I believe to be the superior solution, albeit not in a way which I would have preferred. Pat pushed some updates to X in slackware-current. After utilizing slackpkg to download and upgrade these files, I found that my installation was totally hosed. X would not start, period. Fortunately, I made an image backup of my root partition (/dev/sda2) using dd, and was able to restore most of what I had lost, just minor stuff. As it turns out, KDE 4.9.5 was in that image, and I know that it does not suffer from the screen locker issue nor blanking. I think I'll stick with this setup until the outstanding bugs in 4.10.x are fixed to my satisfaction.