diff --git a/contact_map/contact_map.py b/contact_map/contact_map.py
index 7f730eb..ea069c6 100644
--- a/contact_map/contact_map.py
+++ b/contact_map/contact_map.py
@@ -1,6 +1,8 @@
 """
 Contact map analysis.
 """
+# Maintainer: David W.H. Swenson (dwhs@hyperblazer.net)
+# Licensed under LGPL, version 2.1 or greater
 import collections
 import itertools
 import pickle
@@ -59,6 +61,9 @@ def _atom_slice(traj, indices):
     if traj._have_unitcell:
         unitcell_lengths = traj._unitcell_lengths.copy()
         unitcell_angles = traj._unitcell_angles.copy()
+    else:
+        unitcell_lengths = None
+        unitcell_angles = None
     time = traj._time.copy()
 
     # Hackish to make the smart slicing work
diff --git a/contact_map/plot_utils.py b/contact_map/plot_utils.py
index ba2ff56..4d86260 100644
--- a/contact_map/plot_utils.py
+++ b/contact_map/plot_utils.py
@@ -42,7 +42,7 @@ def ranged_colorbar(cmap, norm, cbmin, cbmax, name="Partial Map"):
     new_norm = matplotlib.colors.Normalize(vmin=cbmin, vmax=cbmax)
     sm = plt.cm.ScalarMappable(cmap=new_cmap, norm=new_norm)
     sm._A = []
-    cb = plt.colorbar(sm)
+    cb = plt.colorbar(sm, fraction=0.046, pad=0.04)
     return cb