#22 drawing errors

[Anonymous]

Using waimea 0.4.0 I frequently get drawing errors on
the grippers at the bottom of a window. It happens
randomly when I switch from one window to the next, and
takes the appearance of a random repeating pattern with
the colors of the theme. Sometimes it takes a while to
happen, other times a very annoying pattern will appear
and it will take several focus changes to get it to
redraw the way it's supposed to.