Hack to kwin/qtcurve to allow for shadows to appear on client decorated windows, such as chromium or steam.
This is really hacky and iirc discouraged by kwin upstream, so your mileage may vary. Needs a proper rewrite/cleanup.
I don't take any responsibility for breakage.
Just patch kwin (kdeworkspace) and qtcurve with the appropriate patch.
Kudos to the kwin and qtcurve team.