Steps to reproduce the issue:
1. run a fullscreen-capable application (iceweasel or remmina), put it
in fullscreen mode.
2. use xrandr to change the screen size, by either changing the physical
resolution, or change the scale option. example:
xrandr --output LVDS1 --scale 1x1.28
3. The fullscreen window does not resize itself thus only occupies
partially the new screen size. (note that maximized window is *not*
affected by this bug)

metacity does not have this problem. run "metacity --replace" and
repeat the above step, the fullscreen window resizes correctly.

Thanks.