BUG: add comment that addresses the issue

Author: alexandercbooth

pandas/tools/plotting.py

@@ -149,6 +149,7 @@ def _mpl_ge_2_0_0():
     except ImportError:
         return False
 
+
 if _mpl_ge_1_5_0():
     # Compat with mp 1.5, which uses cycler.
     import cycler
@@ -359,6 +360,8 @@ def scatter_matrix(frame, alpha=0.5, figsize=None, ax=None, grid=False,
     density_kwds = density_kwds or {}
 
     # workaround because `c='b'` is hardcoded in matplotlibs scatter method
+    # only set default for `c` if `color` kwarg not supplied
+    # GH 14855
     if 'color' in kwds:
         pass
     else: