When drawing graphs using the graph module, the resulting graph may be drawn on top of the axes surrounding the graph area, producing ugly images. A minimal example:
begin graph
let d1 = x
d1 line color red
end graph
Zoom into the upper right or lower left corner and note that the red line is drawn above the axis. The correct behavior is to either draw the axes on top of the graphs, or clip the graphs so they don't cover the axes. I'm using GLE 4.2.0