TH2F plot getting cut off

I have a TH2F that I’m plotting using the cont4z option and for some reason the borders are being cut off in the display. Here’s the declaration of the histogram:

TH2F * structure_sizes_2D = new TH2F("structure_sizes_2D","Size of structures as a function of dual base probs;base_prob;Ln(pixel count);Counts",20,0,20,10,0.01,0.04);

And the picture is attached. Any idea why the border is there? Thanks!

The CONT4 option is done by showing a surface plot (SURF2) from top. Surfaces are drawn by connecting the bin centers. That’s why there is a margin around the plot (half a bin). Use option COL instead.