Using metacity-2.4.0, I create a new window in an empty workspace.  In this
case, a gnome-terminal.  The default geometry is 80x24.  The window is
aligned with the top and left border of the workspace - the corner.

alt+space to bring up window menu, r to resize.  down arrow to make it
longer.  beyond 80x26, it ceases.  i can make it 80x1, but nothing longer
than 80x26.  if i then move it one space down - alt+space, v, down arrow
once - can resize it with alt+space, r, and the up arrow until the top of
the window is pushed to workspace boundary.  then if i continue press the
up arrow, the bottom of the window is extended to the desired length.

this appears to happen only when a window is in the top left or top right
corner of the workspace.  it doesn't happen in any other positions i can
see, and the application doesn't matter as long as it permits resizing.