The attached file is an excerpt from a program. It creates a single window,
undecorated, on top of other windows and in the upper left corner of the
screen. At least it should do that, and it used to. At the moment, it only
achieves parts of this, the resulting position is wrong.

The program uses XCB, but I have tried an earlier version of the program that
uses Xlib, and it suddenly has the same problems, so that is not the cause for
problems.

I have tried openbox, sawfish and icewm, and all three the WMs work as
expected. I have also tried fluxbox 1.1.1+dfsg2-1 and it shows the same wrong
behaviour as the current version. If that had always been the case, I'm pretty
sure that I would have noticed before, because I've been running fluxbox for
ages. That again makes me wonder if this is really just a problem with
fluxbox, at least I suspect other influences, like possibly in the X server.


Cheers!

Uli