[dwm] slock bug/misfeature?

Hi,

I tried running slock instead of my usual xtrlock this night and I think
there's a bug (or perhaps just a misfeature):

when a window shows up (say a dialog) after launching slock it appears
over the black background which kind of defeats the purpose of having a
black window at all. Of course I still need to enter the password to
access the computer, so this part works OK.

Best,

-- 
[a]