winex11: manage one more case

[Dan Kegel]

The discussion in http://bugs.winehq.org/show_bug.cgi?id=3997
and offline makes it seem as if the z-order problem is very
hard to get right.  Yet there is some urgency to solving this
problem for at least the most popular apps that suffer from it.
So, perhaps it's time to consider solving it wrong.

I wrote:
> +    /* photoshop cs installer wizard should not hide "please close" dialog */
> +    if (style == (WS_CLIPSIBLINGS|WS_POPUP)) return TRUE;

Now, I realize this is probably wrong, but it gets both Photoshop CS's
installer and Bricscad 8's installer past their z-order problems.
What would it break?  (If it's not obvious, I'm not very well
informed about window styles, window management, and all that.)

If the patch I proposed would break too many things,
perhaps we should make it conditional on particular
executables, with the list of executables configurable via
the registry and winecfg, as we do with library overrides.
That way the damage would be limited.

Thoughts?
- Dan