Shaped frames (even the example) cause warning window

Hi,

I just found that the “ShapedWindow.rbw” example (from bigdemo) causes a
Warning Dialog window to appear when you click the display button,
saying: “Ignoring attempt to set cHRM RGB triangle with zero area”.
After some experimenting with shaped frames I cannot make this window
not to pop up - this is very annoying, since I don’t want to click it
away every time my application is run. Is there any way to get round it,
or at least to suppress that?

ruby -v: ruby 1.9.1p376 (2009-12-07 revision 26041) [i686-linux]

Marvin